THE BOSTON RESERVOIR.

THE HIGH BRIDGE AT HARLEM.

The mention of the High bridge at Harlem, and its connection with the aqueduct which brings the Croton water to the city of New York, suggests some notice of the aqueduct by which water is brought to the city of Boston, Massachusetts. So early as 1795, an association was formed in Boston for supplying the inhabitants with pure water; and for years it was brought from Jamaica pond, in Roxbury, some four miles distant, in logs which were bored for the purpose. These logs were capable of supplying some fifty thousand gallons daily, which could be raised to the hight of forty-nine feet above tide-water. This supply, however, was soon found inadequate to the wants of the city, though in 1845, some fifteen miles of pipes had been laid, and some three thousand houses were regularly supplied with water. A plan was therefore formed in 1845, to supply the city with water from Lake Cochituate, or Long pond, as it was formerly called, about twenty miles west of Boston. This lake covers a surface of some six hundred and fifty acres, is seventy feet deep, and drains the springs, it is supposed, of some eleven thousand acres. Its elevation is one hundred and twenty-four feet above spring-tide, so that the descent is such as to make the conveyance of water to the city both easy and sure. The water is carried in a brick conduit or tunnel, high enough for a man to walk upright in, as far as the receiving reservoir in Brookline, and from there is taken in thirty and thirty-six inch pipes to the distributing reservoir on Beacon hill, in Boston. It is this reservoir, a view of which is given in the cut beyond, from which the water is distributed in pipes throughout the city. The average daily supply of water needed for the present population of Boston, is about five million gallons. The water-works are capable of supplying twenty million gallons daily; and the Cochituate lake is capable, (by laying down another main pipe,) of supplying forty million gallons daily. The supply of the lake is fully equal to the wants of half a million of people.

AQUEDUCT AT THE PEAT FOREST CANAL.

This aqueduct forms part of the Peat Forest canal, which is a branch of one of the canals extending out from Manchester in England. The latter city is the great center of the cotton manufacture for England, and perhaps the principal manufacturing town in the world. Before the invention ofwhat was called thespinning-frame, in 1767, the entire imports of cotton into Great Britain did not amount to four million pounds a year, and the value of exported cotton goods was not over one million dollars. But so rapid has been the improvement of machinery, and the increase of manufactures, that in 1840 the imports of cotton amounted to the prodigious quantity of nearly six hundred million pounds, of which nearly five hundred million were manufactured. And in 1854, these imports amounted to nearly nine hundred million pounds, of which about the same proportion was manufactured as in 1840. Of this immense manufacture, Manchester is the center; and to this may be added various other manufactures, as in silks, worsteds, machinery, &c., &c., &c. As a consequence of this immense business, seeking, of course, outlets to market, Manchester has become a great center of internal navigation. So early as 1761, the Duke of Bridgewater’s canal was constructed; and this was soon followed by the Bury and Bolton canal, in 1791; by that to Ashton and Oldham, in 1792; and by that to Rochdale, in 1794. And these, again, are connected with other canals in such a manner as to establish an easy communication with the eastern, central and southern counties, including the ports of Hull, London and Bristol, as well as Liverpool, which, of all others, istheport of Manchester. It ison one of these side canals that the aqueduct, a view of which is given in the cut above, is located; or rather, it forms part of the canal itself. It is not so much to be noted for its greatness or expensiveness, as for the fact that it was among some of the earliest structures of this kind, which have since become common wherever canal navigation is known.

AQUEDUCT ON THE PEAT FOREST CANAL.

Atunnel, in engineering, is a subterranean passage cut through a hill, or under a river, for the purpose of carrying a canal, road, or railway, &c. One of the most remarkable works of this kind, ever executed, is the tunnel under the river Thames, planned by Mr. Brunel, and successfully executed under his direction. Two previous attempts had been made to carry a tunnel under the river; one in 1799, and the other in 1804; but both were unsuccessful. In 1824, however, an act of parliament, authorizing operations on the plan of Mr. Brunel, was obtained; and shortly after the work was commenced. A short account of the progress of the work will probably be the best mode of conveying a notion of the nature and difficulty of tunneling in general.

Mr. Brunel began his operations by making preparations for a shaft fifty feet in diameter, which he commenced one hundred and fifty feet from the river on the Surrey side; this he effected by constructing on the surface of the ground a substantial brick cylinder of that diameter, forty-two feet in hight and three feet in thickness. Over this he set up a steam-engine, necessary for pumping out the water, and for raising the earth to be taken from within the cylinder, and then proceeded to sink it bodily into the earth. By this means he succeeded in passing through a bed of sand and gravel twenty-six feet deep, constituting, in part, a quicksand, and in which the drift-makers of the former undertaking had been compelled to suspend their work. The cylinder having been sunk to the depth of sixty-five feet, the horizontal excavation was commenced at the depth of sixty-three feet; and in order to have sufficient thickness of ground to pass safely under the deep part of the river, the excavation was made to descend two feet and three inches in every hundred feet. This excavation is thirty feet wide, and twenty-two and a half feet high, and the process of making it may briefly be described as follows.

It was accomplished by means of a powerful apparatus of iron, called ashield, and which consisted of twelve large frames, standing close to each other, like so many volumes on the shelf of a book-case, these frames being twenty-two feet in hight, and about three feet in width. They were dividedinto three stages or stories, thus presenting thirty-six cells or chambers for the miners. The front of each one of these cells was protected by narrow boards, technically called polling-boards, each of which was separately held in its place by an apparatus constructed for the purpose. The miner commenced by removing the upper polling-board in his division of the shield, thus exposing a small portion of earth; into this earth he made an excavation of six inches in depth, throwing the earth behind him, from whence it was removed to the mouth of the tunnel, and from thence raised by steam to the surface of the ground. He then replaced the polling-board, causing it to press against the face of the newly excavated earth, and thus advancing it six inches beyond the other polling-boards of his division. Then successively taking down the remaining boards, excavating the earth six inches behind them, and replacing the boards six inches further in than before, he very soon had advanced that distance over the whole length of his division. All the other miners in the thirty-six cells having done the same, the framework was moved forward, and six inches more of earth removed. It was in this way, by these slow degrees, that the work was finally completed. As the frame-work advanced, it was closely followed by a solid mass of brick-work, inclosing two arched passages. These two passages were separated by a solid wall, three and a half feet at the top and four at the bottom. Other arches, however, were formed in this wall, for the purpose of opening a communication between one tunnel and the other. The whole of the brick-work is laid in Roman cement, and each archway is finished with a lining of cement, a carriage-road, and a narrow foot-path adjoining the central wall.

This immense enterprise was not finally completed without serious delay and apparently insurmountable obstacles. The works were thrice interrupted: in 1826, by the breaking off of the clay, leaving the shield exposed to the influx of the land-water for six weeks; also in May, 1827, and in January, 1828, when the river broke in and filled the tunnel. This was quickly remedied, however, by filling the holes or chasms with strong bags of clay; the structure, on clearing the tunnel of the water, being found in a most satisfactory state. Some time later, the works were suspended for seven years, owing to the want of funds. Parliament, however, after repeated applications, granted an advance for their completion, and the works were resumed and continued, till they were brought to a successful termination. The cost of the tunnel, with the approaches on both sides of the river, was about three million and a half dollars; much less than the cost of the modern metropolitan bridges which span the Thames between Surrey and Middlesex.

RAILROAD TUNNELS.

The establishment of railroad communication has given rise, both in this country and Europe, to some stupendous undertakings in the way of tunneling; one or two of which are worthy of notice as illustrating the nature and extent of this kind of work. And the first of these which we shall mention, and one of the most remarkable, is the Box tunnel on the Great Western railway in England. This tunnel pierces what is called Box hill, between Chippenham and Bath, part of which is four hundred feet above the level of the track. It is ninety-six hundred and eighty feet long, thirty-nine feet high, and thirty-five wide to the outside of the brick-work. The shafts for making and ventilating it, are thirteen in number, and vary in depth from eighty to three hundred and six feet. The excavation amounted to four hundred and fourteen thousand cubic yards; and the brick-work and masonry, to more than fifty-four thousand cubic yards. The number of bricks used, was thirty million. A tun of gunpowder and a tun of candles were consumed every week for two years and a half; and eleven hundred men and two hundred and fifty horses were kept constantly employed for all that time. For a considerable distance the tunnel passes through freestone rock, from the fissures of which there was, at times, an immense influx of water, by which on one occasion the works were interrupted for a period of nine months. On another occasion after an irruption, water was for some time discharged by the engine at the rate of thirty-two thousand hogsheads a day. This tunnel is on an inclined plane of one in a hundred. There are several other tunnels of great extent in England, such as the Kilsby tunnel, on the London and Birmingham road, which is over seven thousand feet long; and the tunnel from Wapping to Edge hill, on the Liverpool and Manchester road, which is over six thousand feet long, and quite a number of others of five thousand, four thousand, three thousand feet long, &c. One of these remarkable tunnels, is that on the South-eastern or Dover railway, a view of which is given in the cut on the following page, which passes through what is called Shakspeare’s cliff, at Dover, (thoughthecliff to which the poet alluded has been undermined and thrown down, and the name is now given to another part of the same range,) on the north side of the British channel. This cliff is a high bluff of chalk, on the west of the town, the white appearance of which gave the name ofAlbion(white) to England. There are two openings in the tunnel; and through these the whizzing locomotives fly along the dizzy precipice, as if it were an ordinary highway. There is, also, asecondtunnel in the same cliff. This last iscalled the Abbot’s-cliff tunnel, and is about a mile in length, coming out on the face of the rock about sixty feet above the sea. The track passes along the front of the rampart for about a mile, and then enters the Shakspeare tunnel, which is also about a mile in length. Thence, again, it issues on the face of the cliff, and proceeds to the station at Dover.

TUNNEL IN SHAKSPEARE’S CLIFF.

In the United States there are quite a number of railroad tunnels of great extent. One of these is the Blue Ridge tunnel, in Virginia, the length of which, when completed, will be forty-two hundred and sixty feet, of which more than half is already (1855) finished. The work has been commenced on each side of the mountain, and is progressing at the rate of about fifty feet a month, at which rate of progress it would take about three years to complete it.

But probably the most gigantic work ever proposed in the way of tunneling, is the Hoosic tunnel, on the line of the Troy and Greenfield railroad, by which it is designed to shorten the passage from the former place toBoston. This immense tunnel it is proposed to carry through the solid rock of the mountain for a distance of some four miles, and to make it wide enough for a double track for the railroad; the expense of doing which is variously estimated, at from four million to six million dollars. By the ordinary method of drilling and blasting, it would take so long a time, and require so large an expenditure, that all idea of thus accomplishing the work has long since been given up, if, indeed, it was ever entertained. And the plan is, by immense boring machines, constructed for the purpose, to make grooves round large masses of the rock, and when these latter are broken up by blasting, to remove them piece by piece. Several such machines have been invented and constructed with reference to this very work, and one or two of these have been found successful in practice, though the immense strain caused by the boring is such as to require corresponding strength in the borer. To give the necessary ventilation, and now and then light to the tunnel, both when in the course of construction, and especially when finished and in use, it is proposed at proper intervals to sink dry wells, or openings from the top of the mountain, down to the tunnel itself; so that the constant stream of air entering the mouth of the latter, at either end, may be always and steadily passing up through these chimneys or ventilators, thus carrying off the smoke of the engines, or any impurities of the otherwise stagnant air. The work, when completed, if it ever is, will be a monument of enterprise and perseverance, unrivaled in the history of tunneling in this or any other country of the world.

This was a celebrated brazen image of Apollo, of the enormous hight of one hundred and five Grecian, or one hundred and twenty-five English feet, placed at the entrance of one of the harbors of the city of Rhodes, (anciently Rhodus,) which is about twenty miles from the coast of Lycia and Caria, in the Mediterranean sea. The island of Rhodes is about one hundred and twenty miles in circumference, and was early occupied by a colony of Greeks from Crete and Thessaly, who in time became both wealthy and powerful. Their capital city was on the east of the island; it was built in the form of an amphitheater, and had numerous splendid buildings, among which was a temple to Apollo. Having for a time submitted to the power of Alexander the Great, they afterward refused to assist Antigonus in his war with Egypt, when he sent his son Demetrius against them, with an immense fleet and army. They, however, being aided by Ptolemy, king of Egypt, were enabled to repulse his forces and to oblige him to agreeto a peace. And he being thus reconciled to them, in admiration of the courage they had displayed, presented to them all the engines he had employed in the attack, by the sale of which, for three hundred talents, they raised the famous colossus, a view of which is given in the cut.

THE COLOSSUS OF RHODES.

This immense statue, as already said, was of brass, and was erected in honor of Apollo, the tutelary god of the island, in acknowledgment of the protection he was supposed to have rendered the Rhodians in their recent conflict. It was the workmanship of Chares, (a pupil of Lysippus, a celebrated sculptor and statuary of Greece,) who, with an assistant, was engaged in the work for more than twelve years. The hight of the statue, as already said, was one hundred and twenty-five feet; its thumb was so large that few people could grasp it; and the fingers were each larger than the bodies of statues of ordinary size. It was hollow, and to counterbalance the weight, and render it steady on its feet, its legs were lined with heavy masonry; and within them, were winding staircases leading to the top of the statue,from which one could easily see Syria, and the ships sailing to Egypt. It is supposed to have stood, with distended legs, on the two moles which formed the entrance of the harbor; but as the city had two harbors, one twenty, and the other fifty feet wide at the entrance, it has been supposed to have been at the narrowest. It bore a light, or lantern, so as to serve as a light-house; but whether on the head, or in one of the hands, as represented in the cut, is not certainly known. The statue was erected B. C. 300, and after having stood about sixty years, was thrown down by an earthquake. After its fall, the Rhodians solicited help from the kings of Macedonia and Egypt, and in other countries, to enable them to restore it; and so great was the commercial importance of Rhodes, that their appeal was promptly met by magnificent gifts; but the oracle at Delphos forbade them again to raise the colossus. The statue then remained in ruins for the space of eight hundred and ninety-four years, when, in the year 672 A. D., it was sold by the Saracens, who were then masters of the island, to a Jewish merchant of Edessa, who loaded nine hundred camels with the metal which had composed it, and which, estimated at eight hundred pounds for each camel-load, would have amounted to seven hundred and twenty thousand pounds’ weight.

The character of Rhodian art was a mixed Græco-Asiatic style, which seems to have delighted in executing gigantic and imposing conceptions; for beside this celebrated colossus, (which was one of the seven wonders of the ancient world,) there were three thousand other statues adorning the city; and of these, about one hundred were on such a scale of size and magnificence, that the presence of any one of them would have been thought sufficient to dignify almost any other spot. The architecture of Rhodes was of the most stately character: the plan of the city was by the same architect who built the Piræus at Athens; and all was designed with such symmetry, that Aristides remarks, “It is as if it had been one house.” The streets were wide, and of unbroken length; and the fortifications, strengthened at intervals with lofty towers, did not appear, as in other cities, detached from the buildings which they inclosed, but by their boldness, and decision of outline, hightened the unity and conception of the groups of architecture within. The temples were decorated with paintings, by Protogenes, Zeuxis, and other celebrated artists of the school of Rhodes; and of one of these pictures, it is said, that when taken to Rome, it was the object of universal admiration. The island, after passing through various fortunes, has, for a long time, been part of the Turkish empire.

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