The Story of the Hoosac Tunnel

THE observant traveler in our Northern States cannot have failed to notice, within the last few years, as the long trains of freight-cars sweep by him, bow frequently appears, lettered distinctly on their sides, the sign " Hoosac Tunnel Line.”It greets his eye all the way from Massachusetts Bay to the Bay of San Francisco, and from the Ohio to the Red River of the North. Wherever corn and wheat grow or swine and cattle feed on the Western prairies, there will be found the cars, bearing that conspicuous sign, waiting to bring their portion of these products to the distant East, and carry back in return the various fruits of its industry. Perhaps beneath that general sign he may notice the words “ Foreign Freight,” which indicate that the cars so marked are destined to discharge their contents, whether of grain or live stock, into vessels which throng the wharves of Boston, ready to bear their burden to the shores of Europe. But, wherever these cars are met, they tell of a feat of engineering which stands among the most noteworthy mechanical and scientific achievements of our time.

It will surprise some, probably, to learn that the project of a tunnel through the Hoosac Mountain dates so far back as it does, and what was the purpose for which the tunnel was originally designed.

The enterprise of uniting the Western lakes with the Hudson River by means of the Erie Canal, which has given lasting fame to De Witt Clinton, aroused in the merchants and manufacturers of Boston and its vicinity a desire to share in the advantages of traffic with the growing West, thus to be opened. Accordingly, they conceived the plan of a canal which should extend from Boston and meet the Erie Canal at Albany, thus putting Boston in as favorable a position for the trade of the West as New York ; while they hoped also to retain the trade of the central and more distant portions of Massachusetts, which the facilities of transit by the Connecticut River were threatening to take away. Railroads had not then come into being, for this was as far back as 1820, and the first road, the Stockton and Darlington, in England, was opened in 1825. It was a canal which the enterprising people of Boston planned, and a tunnel through the Hoosac Mountain was a part of their canal scheme. And so favorably was their project regarded that early in 1825 the legislature of Massachusetts appointed commissioners “ to ascertain the practicability of making a canal from Boston Harbor to Connecticut River, and of extending the same to some point on the Hudson River, in the State of New York, in the vicinity of the junction of the Erie Canal with that river.” The commissioners accordingly surveyed two routes, a northern and a southern. The northern was reported to be the more feasible. West of the Connecticut it was manifestly so, as it had the natural valleys of the Deerfield and Hoosac rivers, forming a continuous and very direct course from the Connecticut to the Hudson, separated only by the intervening Hoosac Mountain. But that was a formidable intervention. It was true, indeed, that the northern branch of the Hoosac and the western of the Deerfield originated near each other, in a depression on the crest of the mountain. But this point of common origin was considerably northward of the general east and west course of the contemplated canal, and at an elevation of two thousand feet above tide-water. To carry the canal up the bed of these streams would be attended with much difficulty, while the increased distance of eighteen miles and the numerous locks required would not only render the canal expensive in construction, but make its navigation tediously slow. Accordingly, it was proposed to go through the mountain instead of over it, and the engineers gave a very encouraging report, on the score of expense, in favor of the tunnel. It was estimated by them that a tunnel four miles in length could be constructed for less than a million of dollars, while to go over the mountain would cost more than two millions, and the necessarily slow progress through the numerous locks would consume at least eighteen hours, or nearly two days of traveling time, whereas the tunnel could he traversed in an hour and a quarter. The balance was clearly in favor of the tunnel, and as there was at that time a widespread feeling in the old States in behalf of internal improvements, as they were called, and a strong desire to connect New England with New Orleans and the Southwest by a continuous interior water communication, the success of the enterprise seemed assured. The entire cost of the proposed canal from Boston to the Hudson was estimated at $6,000,000. It was presumed that the State of Massachusetts would grant a loan to further the work. It was expected also that the tax upon sales at auction and some other sources of income would be appropriated for the construction of the canal; and in accordance with the sentiment and practice of that time, strange as it may now appear to us, it was also hoped that the aid of a lottery would be authorized. The commissioners, however, felt constrained even then to offer some argument in favor of such a license. And this was their course of reasoning. Having ascertained that $250,000, probably, were annually expended in Massachusetts in the purchase of lottery tickets, notwithstanding the absolute prohibition of the traffic, and adverting to the fact that lotteries have been used for various excellent purposes, they urge that “ if an unabatable evil does exist, let it be converted to the best possible purposes,” — which in this case, of course, would be the building of the desired canal. The commissioners also say, “ they would be the last among their fellow-citizens to sanction immorality, or impair the omnipotence of justice, but with deference offer such remarks as may tend to the development of truth, the confirmation of what shall be found salutary, and the rejection of that which is supererogatory in our generally most excellent code of laws.” The argument of the commissioners then closes with the very pertinent and practical announcement that, “ should a lottery be resorted to as one of the means of raising funds, it can be affirmed with confidence that $20,000 may be thus annually obtained, and probably a much greater sum.”

Copyright, 1882, by HOUGHTON, MIFFLIN & Co.

At this remove of time, one can hardly read without a smile the fervid rhetoric with which the commissioners clothe their report. The construction of this canal would appear to be the great work of that age, something upon which the future of the old commonwealth is wellnigh staked, and in which the whole country is greatly concerned. Patriotism is appealed to, and the traditionary enterprise of Massachusetts is invoked in behalf of the project. The hardihood and perseverance of her sons are adverted to in connection with the settlement of the new States of the West. And this leads the commissioners to indulge in the following lofty strain : “ Shall it then be said that their sires, and those who have been reared and dwell in the land of their nativity, have degenerated ; that Massachusetts has lost her pristine energy, and is doomed to witness the grand progress of internal improvement in more youthful States, and linger in the rear of this eventful age, when the march of the human race, to its most exalted destinies, has acquired an impetus unprecedented in the annals of the world? The whole people will indignantly answer, No. They will merit and maintain the reputation which their ancestors acquired, firmly meet the moral and physical demands of the times, and urge forward those public works which are required to extend and increase the facilities of intercourse with every section of the Union. They will neither be appalled by the difficulties which must be encountered, nor by the expense which will necessarily be incurred. What their wants demand they have the spirit and ability to achieve; for to free and enlightened citizens nothing is impossible which the public good requires should be accomplished.”

But the rhetoric and the appeal to Massachusetts spirit were wasted on the air. The day of canals was passing away, except in Holland. The day of railroads was at hand. The English miners had for some time been using tramways for the conveyance of their coal, and the Stockton and Darlington road, for passenger transportation, had been opened in the same year in which the canal commissioners were appointed, and was already proving a success. The Liverpool and Manchester was in process of construction. Two years later a short road was built for freight purposes, — the first road in this country,— from the Quincy granite quarries to tidewater. The breath was taken out of the canal project. A survey was undertaken, by direction of the Board of Internal Improvement, in the years 1827, 1828, for a railroad for both freight and passenger service from Boston to Albany. Three routes were surveyed, a northern, a middle, and a southern ; the first corresponding very nearly to the northern one which had been explored for a canal, and embracing the Hoosac Tunnel as one of its features. The route adopted was essentially that of the present Boston and Albany Railroad. This line was chosen for the two reasons that it offered the most feasible point for crossing the Berkshire range of mountains, and because it passed through a more populous portion of the State than the northern route ; the population of the towns through which the Boston and Albany road passes, and the towns west of Middlesex within ten miles of the line, being set down then as 137,175, while the population of the northern line was 115,892.

But as there were reformers before the Reformation, so, it would seem, there were railroad men before railroads. It has been claimed for the late Dr. Abner Phelps, of Boston, that he advocated the project of a railroad across the State of Massachusetts twenty years at least before the survey for a canal, and more than thirty years before the Boston and Albany road was built. In the year 1806, Mr. Phelps, then a senior in Williams College, read an account of some of the tramways which were at that time in use in the English coal regions. The account started in his mind the idea of a railroad to be used for the general purposes of public transportation. So firm a hold of his mind did the conception take that two years later, in 1808, he wrote as follows to his brother, who was then a member of the legislature of Massachusetts: “ I see by the papers the legislature of New York has before it a proposition for a canal from the Hudson River to the Great Lakes. If they succeed, perhaps we may extend it through to Boston. But I believe it will be found that railways are better fitted to the climate and business of this country than canals. I wish you would propose a railway from Boston to Albany. Make it a great state road. The counties make roads ; why not let the State make one ? This will bring up a subject which ought to be investigated, and people had better talk on such a subject than to be always discussing politics to no profit. Please, sir, to think of it; and if you see it in the same light that I do you will propose it. Were I in the legislature, I should not hesitate, but would move it as the first subject of attention.”But his suggestion was not acted upon. The time for railroads had not yet come in this country. The project of Mr. Phelps slumbered in his own bosom until the year 1826, when, being himself a member of the legislature, he presented, on the second day of the session, the first proposition for a railway ever laid before any American legislature. It led to the appointment of a committee, in which he was associated with such men as George W. Adams and Emory Washburn, afterwards governor of the State, who were directed to inquire into the “ practicability and expediency of a railway from Boston to the Hudson River at or near Albany.” Their report led to the appointment of the commission for a survey of a route for a railway, which resulted, as we have seen, in the construction of the present Boston and Albany Railroad.

Of course, after the building of the railroad was begun, nothing more was said of the canal, or, for a time, of a tunnel through the Hoosac. The people of Massachusetts counted it a great acquisition to get any direct channel of communication with the fertile and growing West. It is interesting also to notice just what expectations were entertained at that day in regard to railroads. Their chief value was supposed to be for freight purposes, the diminished friction of wheels running upon smooth rails enabling a greater weight to be drawn with the same power than upon ordinary roads, in consequence of which the cost of transportation would be lessened. The acceleration of speed and the saving of time were not much thought of. There was no intention, either, at first, to use steam-power in drawing the cars. Although the English had successfully introduced the locomotive on the few roads they had built, coal was then so much dearer and the cost of horse-power so much cheaper with us than in England, that it was deemed a matter of necessary economy to employ horse-power, as on our street cars now. The economy of power went so far, even, that it was proposed to let the horses themselves ride, in going down the grades. In a note to their report the Board of Directors of Internal Improvements say, “ The labor of the horse may be still further relieved by providing a platform, placed on small wheels, on the long descents, on which the horse himself may ride. This expedient, singular as it may seem to persons unaccustomed to observe the ease of locomotion on a railroad, is adopted with success on the Darlington and Mauch Chunk railroads, and the horses eat their provender while they are returning to a point where their labor is to be resumed.”

The commissioners estimated that the freight cars could be drawn at the rate of three miles an hour, by which means goods could be transported from Boston to Albany in four days. They expected, by having relays of horses once in twelve miles, to attain for the passenger cars a speed of nine miles an hour. The track was to be double, with a flat rail, two inches wide and three eighths of an inch thick, fastened by iron pins into stone sleepers or blocks, about six feet in length and a foot square, resting upon a foundation wall two feet and a half in depth. In the actual building of the road the mode of construction was somewhat changed. Experience had shown that when the rails were fastened to stone sleepers the road was too rigid, and it was better to lay them upon a somewhat yielding wooden foundation.

The road was at first constructed only as far as Worcester. Subsequently another corporation was formed, known as the Western Railroad Company, who built a road from Worcester to Springfield, and finally to Albany, though it did not reach the latter city until 1842.

In the fifteen years which had intervened between the survey and the opening of the road, the population of the State had largely increased. The northern portion, disappointed by the failure of the canal project, which was to have opened to it communication with Boston and the West, had not forgotten the promised tunnel, and was feeling the need of it more than ever. The railroad through Springfield and Pittsfield was built with steep grades, which rendered it a costly route for the transportation of freight. Accordingly, there arose a call for a road along the central or northern portion of the State, and with more feasible grades, which were to be secured by going through the mountain on the west, instead of over it. It is said that when Loammi Baldwin, the distinguished engineer who completed the first surveys for the projected canal, was carrying on his exploration of the valley of the Deerfield, he exclaimed with fervid enthusiasm, “ It seems as if the finger of Providence had pointed out this route from the East to the West! ” A somewhat less enthusiastic by-stander replied, “ It’s a great pity the same finger was n’t thrust through the mountain.”

The attempt was now to be made to open a passage through this opposing barrier. It was a formidable undertaking. The distance from one side of the mountain to the other, where the Deerfield River strikes against it and is sharply deflected by it, is nearly five miles, and the rock of which the mountain is composed is a tough mica-slate. In 1845, three years after the completion of the Boston and Albany railway, a road had been opened from Boston to Fitchburg; and soon afterwards another was begun, extending from the latter place to the Connecticut River at Greenfield. Finally, in 1848, the Troy and Greenfield Railroad Company, with a capital of $3,500,000, was incorporated, and authorized to build a road from Greenfield through the Deerfield and Hoosac valleys, to connect with a road from the boundary of Vermont to the city of Troy. The length of the road, including the tunnel, was forty miles.

But although the road was desirable, capitalists were slow to engage in its construction. The mountain was a formidable object to attack. Six years passed by, and little money had come into the treasury of the company, and there had been little progress with the road. Surveys for the tunnel were undertaken in 1850, and on the first of January of the following year the directors voted to break ground at once. A few months later they decided to expend a sum not to exceed $25,000 in experiments upon the east side of the mountain, at or near the mouth of the proposed tunnel. The estimated cost of the work was now a little less than $2,000,000, or about double what it was twenty years before, when the canal project was under consideration.

It was felt from the beginning that a work of such magnitude must have the aid of machinery for its execution. Accordingly, a huge machine was built, weighing seventy-five tons, and in the year 1852 was brought face to face with the mountain which it was expected to subdue. It was designed to cut a groove about a foot in width, and corresponding with the circumference of the proposed tunnel. When this groove had been cut to a sufficient depth, the machine was to be drawn back, and the great core of rock left in the centre was to be blasted out with powder, or broken off with wedges. When the broken rock had been removed, the operation was to be repeated. The machine promised well. It actually penetrated the mountain to a depth of ten feet, but then it became hopelessly disabled, and gave evidence that it was not adequate for the work to be done. It was sold subsequently for old iron. Two years now passed without any progress in the work. Meantime the aid of the State had been earnestly sought. The legislature had been applied to, in 1851, for a loan of $2,000,000. The application was unsuccessful. Another, two years afterwards, was also denied, though in both cases committees had reported favorably. Finally, in 1854, the State having consented to give the desired aid, a contract was entered into with E. W. Serrell & Co., under which some work was done. The conditions of the loan were that $600,000 should be subscribed to the stock of the company, and twenty per cent. of it paid in. Then for every seven miles of road and one thousand linear feet of tunnel completed the company were to receive $100,000 of state scrip. These conditions were found to be difficult of fulfillment, and the work advanced slowly. In the same year that the loan was obtained, the legislature authorized the towns adjacent to the road to aid it to the extent of three per cent. of their valuation. But in two years only five hundred and twenty shares were taken, and all the money received on them was $1400 from the town of Adams. The contract with Serrell & Co. having thus practically failed, a new contract was entered into with H. Haupt & Co., the next year, to complete the road, with the tunnel, for the sum of $3,880,000, which soon after, by another contract, was increased to $4,000,000. The work now went on without serious interruption. The contractors were energetic and sanguine. Mr. Haupt revived the project of using machinery, and at an expense of $25,000 had another boring engine constructed, which he was very confident would prove successful. He wrote to General Wool concerning it in 1858: " The slowest progress of the machine when working will be fifteen inches per hour; the fastest, twentyfour inches. A machine at each end, working but half the time with the slowest speed, should go through the mountain in twenty-six months.” This machine never penetrated the mountain an inch, and the work was continued by manual labor, as before. In the latter part of the year 1858 the work had progressed so far that the contractors were able to draw the first installment, $100,000, of the state loan. In 1860, subscriptions to the road still failing, on account of the unwillingness of capitalists to engage in a work attended with so many difficulties and uncertainties, the legislature authorized the application of $650,000 of the state loan to the building of that part of the road situated east of the tunnel, the payments to be in monthly installments.

The progress of the work now seemed assured. But in 1861, owing to a misunderstanding between the contractors and the state engineer in regard to the payment of the installments of the loan, Haupt & Co. gave up their contract, and the work was again stopped.

The undertaking now came into the hands of the State, by a foreclosure of the mortgage which it held as security for repayment of the loan to the Troy and Greenfield Railroad Company. The next year, 1862, a board of commissioners was appointed to investigate the condition of the enterprise, and report what action in the case was most expedient. The commissioners recommended that the State should undertake the completion of the work. Their recommendation was adopted. At this time the tunnel had been excavated for a distance of 4250 feet, or about one fifth of its proposed length. In carrying it so far the State had advanced, in addition to what had been expended of the funds belonging to the company, $1,431,447. It was estimated by the commissioners that it would now require $3,218,323 to finish the tunnel. It will be noticed how, as its construction went on, its cost was constantly increasing. The estimate had advanced from the original mark of less than a million dollars to two millions ; and now to complete it, after so much had been done, it was admitted, would require more than three times the expected cost of the whole undertaking. The engineer who now reported to the commissioners the condition of the road and tunnel, Mr. Laurie, estimated that by sinking a central shaft, and working each way from that as well as from the two ends, the tunnel could be completed in eleven years, or in 1874, which corresponded very nearly with the final result.

Work on the tunnel was resumed, under the direction of the commissioners. They undertook the sinking of the central shaft. The requisite depth of this was 1028 feet. The magnitude of the tunnel undertaking is seen when we consider that only to sink this shaft would require four years of continuous labor and the expenditure of not less than half a million of dollars.

Meantime the work went on, with various obstacles and difficulties. As the miners penetrated farther and farther into the mountain, the labor became more and more troublesome and oppressive from the foulness of the atmosphere, resulting from lack of ventilation and the elimination of noxious gases in the process of blasting. This has always been one of the chief difficulties in tunnel construction. Hitherto, also, the work of drilling had been done by hand labor alone. We have mentioned the employment at the outset of a boring machine and its failure. Other machines were from time to time constructed, but none of them proved practically efficient. About this time, however, there had come into use in Europe various percussion drills. One, used in the construction of the Mont Cenis Tunnel under the Alps, had been introduced here, but was unsatisfactory in its working. Mr. Haupt, one of the former contractors of the tunnel, had given much thought to the matter, and had nearly completed a machine of this class, when his connection with the tunnel was brought to a close. But a percussion drill, known as the Burleigh drill, from its inventor, Mr. Charles Burleigh, of Fitchburg, was tried, and was so effective that it continued to be used until the tunnel was finished, and is now in very general employment for drilling purposes, both in this country and abroad. It is a small and quite simple machine, and contrasts strongly with the great engines which were at first constructed for use on the tunnel. It can he handled easily by one man. It consists of a cylinder with a piston to which a drill is attached. Steam or compressed air is admitted into the cylinder on the two sides of the piston alternately, as in the case of the ordinary cylinder of the locomotive, and the drill is thus driven back and forth with great rapidity. Instead of the sixty strokes a minute made by the hand drill, and then only with frequent intermissions for rest, the percussion drill makes three hundred, and without cessation until the drill is so dulled that it must be replaced by another. To work these drills, several of which were mounted upon a light, movable frame and operated at the same time, the power of the Deerfield River was brought into requisition by means of a dam built nearly a mile above the eastern mouth of the tunnel. The force thus obtained was used to compress the atmosphere to one sixth of its ordinary volume, giving it a pressure of ninety pounds to the square inch. In this condition of tension it was conducted by means of iron pipes to the drilling machines. The compressed air answered a double purpose : by its expansive force it worked the drills most efficiently, and, as it escaped from them after doing its work, served at the same time to supply the miners with pure air from the outer world, and to expel from the tunnel the noxious gases generated by the explosions. The use of compressed air, adopted here for the first time in this country, was a most important aid to the work of constructing the tunnel, and is now regarded as an indispensable adjunct of tunneling operations upon any considerable scale. It was supposed, when the dam was built across the Deerfield River, that it would secure power enough to ply the drills in all the headings of the tunnel, but it was found to be sufficient only for the eastern opening, and steam-engines were established at the western drift and at the central shaft for the purpose of compressing the air for those portions.

The construction of the tunnel, under the supervision and management of the commissioners, went on until 1868, at the close of which year they contracted, on behalf of the State, with Messrs. Shanley, of Montreal, to take the work and complete it. The tunnel was to be twenty-four feet wide and twenty feet high in the clear, and to be finished by the 1st of March, 1874. The price to be paid the contractors was $4,594,268 ; the amount, it will be observed, still increasing as the work went on and less remained to be done.

The Messrs. Shanley prosecuted the undertaking with great energy and skill, carrying it on night and day by relays of men working eight hours at a time, and the final blast which threw down the barrier separating the workmen, and established communication through the mountain from the valley of the Deerfield to the valley of the Hoosac, took place November 27, 1873. It was not, however, until February 9, 1875, that the tunnel was so far completed as to allow the passage of cars. The first freight train from the West, consisting of twenty-two cars loaded with grain, passed through the tunnel April 5, 1875. Passenger trains began to run from Boston to Troy in October of the same year. But it was not until July 1, 1876, that the tunnel was officially declared to be fully open and ready for business.

Thus was accomplished a work which had been prosecuted so long and attended with so many delays, and which had been absorbing such vast sums of money, that it had wearied the patience of the public, and become, in the estimation of many, a gigantic folly. At times the State and all parties, probably, would have abandoned the undertaking, so endless did it seem, and so endless was the expense necessary for carrying it on. Nothing, apparently, but the fact that the State had already sunk so much money in the enterprise induced her representatives to vote further sums, in the hope of making what had been spent of some final benefit to the public.

But the work was great and difficult beyond the expectation of any. When it was begun, none such for magnitude had been undertaken here or in Europe. Experience was wanting, and experience only could make known the difficulties to be encountered. Availing themselves of what has been learned in the prosecution of this work, as well as that of the Mont Cenis Tunnel, carried on in part at the same time, and of our experience in mining during the last twenty years, many would now be ready to engage to make another tunnel through the Hoosac in six years instead of twentyfour, and to do it at a cost, very likely, of $4,000,000 instead of the $14,000,000 expended for the present one.

The Mont Cenis Tunnel is the only one the construction of which can properly be compared with that of the Hoosac, and a comparison of the two will show that the work upon both has been attended with singularly like difficulties and delays; although in the case of the European tunnel two great nations, France and Italy, undertook the project from the beginning, and prosecuted it with their combined skill and wealth, while the Hoosac was begun as a private enterprise, and at best had the aid of only one of our States.

The Mont Cenis Tunnel was proposed as long ago as 1832, but twenty-five years were spent in talk and experiment before the work of construction was seriously and efficiently begun. The aid of machinery was early sought for that as it was for our tunnel, and great expectations from this source were aroused only to be disappointed. Ten years before the process of excavation had taken a practically successful form, the Civil Engineer and Architect’s Journal for 1847 contained the following statement, under the title, Tunneling the Alps: " The Moniteur Belge announces that experiments have been made in order to test the efficiency of a machine, just invented, for the purpose of effecting a new and speedy method of boring tunnels. It is proposed to apply this machine to the construction of the great tunnel about to be commenced in connection with one of the Italian lines. It was placed in front of the web, and effected a bore to the depth of seven inches in thirty-five minutes. At this rate, the new invention will complete upwards of sixteen and a half feet of bore per day, and the proposed tunnel through Mont Cenis will be finished in the space of three years. The experiments have been repeated twice before the first engineers of France, and with the most complete success.”

Nothing more was heard of this so promising machine. It was ten years later, 1857, that the mountain began to be pierced, and the tunnel was not completed until 1871, or twenty years after this boasted machine was to have done it, and only two years before the Hoosac Mountain was pierced. The undertaking was begun by hand labor, but after a time, as in the case of the Hoosac, machine drills were introduced, which, though they did not cheapen the work to any great exent, hastened considerably the rate of progress.

The cost of the two tunnels was nearly the same, that of the Hoosac being, in round numbers, $14,000,000, and that of Mont Cenis $15,000,000. The latter was the longer of the two, being nearly eight miles in extent, but its increased length was offset in cost of construction by the much higher price of labor and materials in this country.

The greatest difficulty in constructing the Hoosac Tunnel was found at the western extremity, for a distance of about half a mile. The mountain as a whole is not unfavorable for tunneling. The rock of which it is composed is not specially difficult to drill, though it is of a tough character, and is not thrown out in as large masses by the explosive charges as some kinds of rock. But it is fairly homogeneous ; the dip of the strata is favorable ; and the arch of the tunnel is, in the main, self-sustaining. At the western end of the tunnel, however, a secondary formation overlaps the primary. This is composed of a silicious rock, quartzose sandstone, and some limestone, much displaced and broken up, the whole overlaid with gravel, clay, and sand, and full of water accumulated from the slope of the mountain, while a brook actually crosses the line of the tunnel. The loose texture of the mountain at this part and the abundance of water seriously impeded the construction of the tunnel, rendering the work both difficult and dangerous, and making it necessary to uphold the roof with an arch of substantial masonry. Not fewer than twenty million bricks were used in this arching, and occasional archings, for short distances, have also been found necessary in other portions of the work, making the entire length of brick arching 7553 feet.

The other principal difficulties were in connection with the shafts which were sunk near the centre and the west end of the tunnel, for the purpose of ventilation and to hasten the work by securing additional faces of rock to which the drills could be applied. The western shaft was 318 feet in depth. The central went down 1028 feet. This was elliptical in form, and fifteen by twentyseven feet in sectional area. Its construction was a difficult and perilous undertaking. The process of blasting was necessarily slower than in the tunnel itself. The stone as it was quarried had to be lifted perpendicularly to the surface in buckets, instead of being put upon cars and rolled to the mouth of the tunnel. Then there was the trouble from water constantly pouring into the shaft. At times fifteen thousand gallons, or five hundred barrels, flowed into it every hour, and had to be removed by powerful pumps, in order that the work of blasting could go on. It was estimated that in one year 13,792 tons of rock and 315,095 tons of water were raised from the shaft. It required, as we have said, more than four years of labor and more than half a million of dollars to carry it down to grade. But it so hastened the completion of the tunnel that the saving of interest on the money invested more than paid its cost.

A sad disaster occurred at this shaft. In the earlier stages of the work it had been attempted to light the shaft by means of gasoline ; but on account of the inflammable character of this substance the plan was abandoned. When the excavation had reached a depth of more than six hundred feet, the endeavor to use gasoline was renewed. But on the very first day of trial, the fluid, contained in a tank near the hoisting machinery, took fire. Almost instantly the flames filled the building, drove the engineer from his post, and cut off all use of the lifting apparatus. Thirteen men had gone down to their work only a few minutes before. Now all communication with them was destroyed, while speedily the burning timbers and a mass of steel drills and other tools were precipitated upon them. How soon they discovered their danger from the fiery shower above or the rising water below no one knows. There was no ladder by which they could come to the surface, even if their way had not been intercepted by the flames. How long the agony and torture of their condition may have continued it is impossible to conjecture. The next morning, as soon as the yet burning ruins could be sufficiently cleared away, a brave miner by the name of Mallory ventured down the shaft, being lowered by a rope fastened around his body. When he came near the bottom, he found no sign of any of his fellow workmen. The shaft had filled with water to the depth of fifteen feet, which, with the fallen timbers, made it impossible to rescue the bodies of the dead. Mallory was drawn to the surface in an almost insensible condition. It was not until the expiration of a year that the machinery destroyed by the fire was replaced, and the water which had filled the shaft was pumped out. Then, after so long a burial, the bodies were recovered and identified.

The further prosecution of the work was accompanied by other serious accidents and many marvelous escapes from injury. When it was nearly completed one poor fellow fell from top to bottom and in an instant was a shapeless mass.

The engineers as well as workmen were exposed to almost constant danger from explosions, the falling of loose stones displaced by the inflowing water, and other sources of harm. As Mr. Wederkinch, the engineer in charge of the shaft, was going down, one day, and was nearly at the bottom, a piece of the machinery above broke into fragments, which came rattling around him. Several pieces of iron struck the cage or bucket in which he stood; one pierced quite through the bottom, which was composed of plank two inches in thickness, but the engineer was unharmed. At every descent of the bucket, it seemed as though those in it were being dashed down the dark pit to almost certain destruction. Speed was necessary, and the machinery was so arranged that the descent of over a thousand feet was made in a little more than a minute. The sensations experienced by those who descended the shaft were peculiar : first there was the sense of rapid, helpless falling through space in the darkness ; then, as the speed was at last almost abruptly arrested, it seemed for a moment as though the motion had been reversed, and one were being as rapidly elevated to the surface again. In all, nearly two hundred lives were lost in the process of constructing the tunnel; and yet, considering the magnitude of the work, the long continuance of labor expended upon it, and the hazardous nature of the explosives used, this was a small sacrifice of life.

For almost twenty years the operatives, sometimes more than a thousand in number, lived, it may be said, in the midst of burning powder or other more violent explosives. It was about the time the tunnel was begun that Sombrero, in Paris, discovered that tremendous explosive, nitro-glycerine, and it became known as a practical agent by its use here. It was found to be safer and much more effective than the ordinary blasting powder, especially when the charges were fired simultaneously, as they were, by means of electricity. The demand for it became so great that a factory for its production was established near the west portal of the tunnel, and more than half a million pounds were used. Great care was observed in its preparation, and a very superior article, known as tri-nitro-glycerine, was the result. Its successful operation in the tunnel has caused it to be used very extensively throughout the country, and it may be considered as the established explosive where operations of any considerable magnitude are carried on. It is so much more powerful than blasting powder — being estimated to have thirteen times its force — that the cost of mining and tunneling is much reduced by its use. The commissioners in charge of the Hoosac Tunnel estimated that there was a saving of $276.85 a day, or $81,557.40 a year, by the use of the nitro-glycerine instead of powder. From their experiments they concluded that the rate of progress in tunneling was more than doubled by this explosive.

The Hoosac Tunnel, with all the delays, mistakes, and disappointments connected with it, is a grand achievement. It is one of the great works of our time. Begun, in its conception, as part of a canal, its completion marks the triumph of the railway, and the great change of inland transportation from the water to the land. Begun with the purpose to make it a part of a canal which, in connection with the Erie Canal, then in process of construction, should form a great line of communication and transport between the new West and the Atlantic markets and manufactories, the tunnel has hardly been completed and brought into use when the question is under debate whether the great Erie Canal itself shall not be abandoned, as no longer able to compete with the railway. Already twenty passenger and as many freight trains pass through the tunnel daily. Every morning through this gateway of the Green Mountains roll the cars whose wheels, the evening but one before, began their revolution at St. Louis, beside the Father of Waters. More than three hundred cars daily carry their burden through this new avenue of transit. Following, to a great extent, the line of the natural water-courses on the route, the easy grades thus secured cheapen the cost of transportation from California and Dakota, from the corn fields of Illinois and the wheat fields of Minnesota, to Massachusetts Bay; and a cent less of freight on each bushel of grain or barrel of flour means millions of dollars saved to the consumers of bread in New and in Old England.

If for nothing else the tunnel would be worthy of notice as a triumph of engineering. Some may think that it was only a question of Patrick with his drill and plenty of gunpowder and time ; and that to go through a mountain is no more than to go through a hill, or a short rock cutting, except that the process is lengthened with the distance. But “ time is money.” It would take fifty years to go through the Hoosac Mountain, beginning at any point on one side, and burrowing to the other. We could not wait for that. No one, not even a state government, would put capital into a work the end of which was to be reached only after half a century. So the tunnel must be begun at more than one point. Here at once is involved a nice problem of engineering. Working simultaneously from opposite sides of the mountain, it is no longer Patrick burrowing through by whatever zigzag course he may chance to take, but these tunnelings from opposite sides must be so directed that they shall finally meet, and fall into an accurate line of adjustment. How shall this be done ? As any one can see, who gives the matter a moment’s thought, a slight deviation from the mathematical line required would cause the two arms of the tunnel to miss each other. The width of the tunnel is twenty-four feet. It is only necessary, therefore, for the approaching excavations to swerve from their true place at the point of expected junction by anything more than half that measure, or twelve feet, in order to slip by each other, and go farther and farther asunder, instead of coming together. Who will measure and set the angle which shall determine the momentous difference in such a case between success and failure ? The tunnel is to be nearly five miles long. Each channel from the opposite sides of the mountain will therefore be nearly two miles and a half in length. The problem, then, is to run two lines of excavation through a mountain, with no visible point in front to aim at, as the engineer has in the open field, and yet to have them so nearly coincident in direction, for a distance of twelve thousand feet each, that they will not miss each other, but form one continuous whole. No Creedmoor rifle needs to be aimed so nicely in order to hit the bull’seye. No allowances for wind to swerve, or the power of gravitation to draw down the ball from its proper course, render the marksman’s problem so difficult of solution as the engineer’s in this case. An error in the sighting of his instrument, amounting literally to a hair’s-breadth, would send the arms of his excavation wide asunder into the bowels of the dark rock, leaving his tunnel no tunnel at all, but only a worm’s track in the mountain. But the problem in this instance was still further complicated. To hasten the completion of the tunnel by providing additional faces on which the workmen could operate, as well as for the purpose of ventilation, it was determined, as we have seen, to sink a shaft from the top of the mountain to the level of the tunnel, midway between the two ends. Two factors were thus at once added to the problem : first, to fix so accurately the point on the mountain at which to begin the downward excavation that when, after working by faith for four years, the estimated time necessary, the miners should have reached the requisite depth, they would be in the exact line of the projected and partly completed tunnel; and, secondly, from that pit in the depths of the mountain, to be able to aim their course in either direction so correctly as to be sure of meeting the company of miners approaching them from both extremes of the tunnel. In short, here were four tunnels to be made at the base of the mountain at one and the same time, and another from the summit perpendicular to them, and all to be exactly in the same plane, on penalty of the failure of the entire enterprise !

It was a difficult problem. But it was solved most triumphantly. When the headings from the central shaft and from the eastern portal came together, as come together they did, their alignments swerved from each other by the almost infinitesimal space of five sixteenths of an inch ! It was an unparalleled feat of engineering. With the best engineering talent of Europe the opposite arms of the Mont Cenis Tunnel had a divergence of more than half a yard. The office and worth of science were admirably illustrated in the case of the Hoosac. It was science, applied science, which built this great thoroughfare of traffic and travel. Its lines and proportions were all ascertained and laid down by scientific calculation. Patrick could pound the drill and light the fuse that would explode the charges of powder ; but without scientific engineering to lay his path for him and mark every drill hole, Patrick would have wandered in the depths of the mountain till doomsday, with his powder and drills, and no practicable tunnel would have been the result.

Let us see if the working out of this purely scientific problem can be rendered intelligible to the general reader. The Hoosac is part of the Green Mountain range, which extends in a north and south direction along the western border of New England. On the east and on the west of it are other ranges and spurs. Indeed, the whole region is one of mountains and intervening depressions. On either side of the Hoosac are the valleys of the Deerfield and Hoosac rivers, and beyond them rise on the west Graylock, the highest peak in Massachusetts, and the Taconic range, and on the east the mountains of Rowe and its vicinity. The Deerfield River, as it comes down from the north, strikes against the flank of the Hoosac Mountain, and is turned abruptly to the eastward, and flows off, winding like a thread of silver among the lofty and overshadowing hills to join the Connecticut. It was determined to start the tunnel on the east, at the point where the Deerfield touches the mountain. Having fixed also upon a point for the western terminus of the tunnel, the next thing to be done was to connect the two by a line over the mountain which should be throughout its course in the same perpendicular plane. In order to do this, a broad path was cut through the forest which covered the mountain, and an approximately straight line run. Then monuments, or sighting posts, were set up on the mountains opposite the Deerfield and Hoosac valleys, and these were brought into range with the summits of the Hoosac and other points fixed along the course by the engineers. The surveys were repeated and the results marked again and again, and in different states of the atmosphere as to clearness, humidity, and temperature; for it is found that the eye sees differently, and that instruments give different measurements, under varying atmospheric conditions. Finally, the law of averages was brought in, and the mean result of the several measurements was taken as the true course, and the line thus laid down was permanently established by means of iron bolts fixed at proper distances on the Hoosac and the adjacent mountains. A notch or minute line in the top of these bolts indicated more exactly the course of the tunnel, and reference was made to these notched bolts, throughout its construction, for the verification of all positions and measurements. Having established this line over the mountain and rangepoints on the adjacent elevations on either side, it was comparatively easy to sight back from those range-points to the mouths of the tunnel, and so push the work into the mountain in the proper direction. But the same care was taken to secure accuracy as in running the line over the mountain, by repeated surveys and measurements, and constant endeavors to reduce all errors to the minimum. How great that care was is shown in the result, as the lines met each other in the heart of the mountain within a small fraction of an inch.

The problem of the engineers was somewhat complicated also by the sinking of the shaft near the centre of the line over the mountain. With that line fixed, it was easy enough to begin a shaft at whatever point on the line should be considered desirable ; and if the shaft were sunk perpendicularly it would of course strike the line of the tunnel beneath. But the shaft was to go down more than a thousand feet, and as it went deeper and deeper it became a matter of increasing difficulty to secure a perpendicular course by means of the plumb line, the dripping of water, falling stones, and explosions of powder or glycerine, occasional currents of air, and other disturbance tending to sway the plumb from its perpendicularity. Even after incasing the lines in boxes, and immersing the plumb bobs in water, to shield them so far as possible from these adverse influences, it was found that at all times, by day and by night alike, the plumb bobs had an oscillating motion of some extent in an elliptical orbit, the ellipse sometimes lying in a direction with that of the tunnel and sometimes across it. Such were the obstacles encountered in this part of the work. But the trouble was not so much in getting the shaft down to the tunnel with a fair degree of accuracy — at least such as would render it available for the purpose of ventilation — as in establishing a line at the bottom of the shaft which should be coincident with that of the tunnel, and on which the work of excavation could be prosecuted in both directions, toward the east and the west, with the certainty of meeting the headings which were approaching from those directions, and thereby shortening the time to be consumed in the whole work. But the engineer in charge of the work at the shaft, Mr. Wederkinch, was equal to the demands upon him. He was a Dane by birth, and not only had the ordinary education of an engineer, but had been employed in a manufactory for making mathematical instruments. The knowledge acquired in this occupation he put to good account now by contriving some ingenious machines to enable him to overcome the difficulties confronting him. After four years of toil and constant watching, the shaft was sunk to the proper level. Then, from that narrow base, that mere well-hole in the depths of the mountain, the courageous engineer struck out right and left in the darkness, and carried forward his channels of excavation with a sublime confidence which was fitly crowned by the result, already mentioned : that he met, at a distance of sixteen hundred feet, the heading which had been driven towards him from the east portal of the tunnel for a space of more than eleven thousand feet, or two miles and a quarter, and the headings coincided almost absolutely.

The length of the tunnel was also calculated in advance from the measurements made in going over the mountain, and when the tunnel was completed it was found that its actual length differed from the estimated by only eighty-five one hundredths of a foot, or three one thousandths of one per cent. in a distance of four miles and three quarters ! It was another triumph of engineering skill, a triumph of science as applied to practical work, and most creditable to the chief engineer, Mr. Frost, and his three assistants, Messrs. Locke, Wederkinch, and Fisher, respectively in charge of the eastern, central, and western portions of the work. The scientific reader will understand at once that the determination of the length of the tunnel from the length of the line over the mountain was made by a system of triangulation, and the application of the familiar theorem for finding the third side of a triangle when two sides and the included angle are given. For the general reader it may be needful to say that the measurements up and down the face of the mountain were made by means of a steel tape-line, one hundred feet long. Each length of this line was regarded as the hypothenuse of a right angled triangle. But it is well known that no power can stretch a line of any considerable length so that it will be absolutely straight. It will always sag, or be curved to some extent. It will break before it can be made straight. But it was necessary to have this measured line from point to point a mathematical line, in order to be able to apply to it the geometrical theorem or principle. A nice calculation, therefore, had to be made of the amount to be allowed for the curvature of the tape-line ; in other words, to determine what length of absolutely straight line each curved line of the successive measurements was equivalent to. Such a calculation was made, and with the result above given. And so the Hoosac Tunnel stands as one of the finest exhibitions of engineering skill and of the application of science to practical life which the world affords. As such it is well worth visiting, whether by the scientific or by the unscientific.

And yet, after all, there is little to be seen of this great work. The passing traveler by the railway, looking from the rear of the train, as it glides into or out of the tunnel, witnesses nearly all that a more protracted visit would enable him to behold. The description we have here given will really afford one more knowledge of this great work of art than he will be likely to gain by a personal inspection. Going to it, he will at the most see only the archway at either end, and the masses of shapeless rock which have been excavated and used in part as an embankment for the railway approaches. He will come to the portal expecting, probably, to look through to the opposite entrance, — at least to see a ray of light from that point; or, if he has been told there is an ascending grade from either end, which would preclude such a sight, he will still expect to look along the symmetrical archway of stone to such a distance within as will give him some impression of the magnitude of the work here wrought. But if ever such a sight were to be had, it must have been before the tunnel was completed and brought into use. And what, after all, is an opening only twenty feet in diameter in a mountain that towers above it to the height of seventeen hundred feet, and is almost five miles from side to side ? How could we expect the light to stream through such a knitting-needle kind of hole ? But whatever may once have been possible, now that scores of trains are daily passing through the tunnel, the original dimness has become blank darkness. A cloud of smoke pervades it through its whole length, wafted backward and forward to some extent by the occasional winds, or creeping slowly out at one portal or the other ; but each passing train adds enough to keep the entire tunnel charged so that practically no one can see more than a few yards or rods, at the most, within the great cavern. No artificial light, not even the head-lights of the locomotives, can penetrate the darkness for any considerable distance. The engineer sees nothing, but feels his way, by faith and simple push of steam, through the five miles of solemn gloom. If there is any occasion for stopping him on his way through the thick darkness, which may almost literally be felt, the men who constantly patrol the huge cavern to see that nothing obstructs the passage do not think of signaling the approaching train in the common way, by means of a red lantern. That would be useless. They carry with them powerful torpedoes, which, whenever there is occasion, they fasten to the rails by means of screws. The wheels of the locomotive, striking these, produce a loud explosion, and this is the tunnel signal to the engineer to stop his train.

N. H. Egleston.