ANCIENT ENGINEERING.

New Zealand Herald, Volume XXVII, Issue 8222, 5 April 1890, Page 2 (Supplement)

ANCIENT ENGINEERING.

We talk a great deal about the wonderful achievements of modern times in canal building, tunnelling, and other excavations, too often forgetting or considering of little account ancient achievements of like character. DIVERTING THE EUPHRATES. The earliest work of magnitude of this character of which we have any direct knowledge is probably the turning of the Euphrates by Cyrus as a means for his entry into Babylon. This work was determined upon only after a two years' siege. The great depth and width of this rivetare sufficient to stamp this piece of engineering work 'as one of vast magnitude and no little difficulty, to say nothing of the fact that its accomplishment led to the downfall of the mightiest city of ancient, or perhaps of modern, times.

THE NEXT GREAT FEAT of this kind was accomplished by Xerxes, 4so 8.C., who cut a canal across the Isthmus of Mount Athos to facilitate his conquest of Greece. The work was herculean in character, especially when we consider the inefficient means for such work at the command of the engineers of those days. His fleet of over a thousand ships was enabled to pass through and thereby avoid the dread dangers of the stormy promontories which had been the ruin of so many ships before his day. THE ORIGINAL SUEZ CANAL We can say but little of this work, as we know of it. only by the excavations which were found by the engineers of the present canal, which follows very nearly the course of the old one. In regard to when or by whom that great work was accomplished, history is silent. THE DRAINAGE OF THE VALLEY OF THE CITY OF MEXICO. As is well-known, the City of Mexico is situated in a deep valley, surrounded by mountains everywhere except at one point where a narrow canyon furnishes a limited outlet for the immense body of water which flows into that valley, especially during the heavy rains which sometimes almost deluge the city and its surroundings. This great danger and discomfort to health and commerce was seen and felt by the early Spanish invaders who took possession of that ancient city, and measures were taken to abate it. The first plan adopted to accomplish this work consisted of an attempt to divert the waters of one of the principal rivers from its natural channel to the outer slope of the watershed, and thus prevent, their reaching the plain of the city. To effect this a channel had to be dug and a tunnel over three miles in length had to be excavated. The work was completed, but it failed to accomplish the purpose desired on account of the tunnel becoming constantly choked with debris. This trouble was remedied by converting the tunnel into an open cut. The original work was begun in 1607, but. the open cut was not, completed until 152 years later. During the accomplishment of the first work it is said that 470,000 natives were employed, and 50,000 perished from sickness and casualties. In the after-work of converting the tunnel into an open cut the labour was enormous. The length of the cutting was about 13 miles, and for the distance of nearly a mile through the rocky divide the width of the opening at the top was from 270 to 360 feet, and the perpendicular depth from 147 to 190 feet For the distance of nearly 3 miles the depth was from 98 to 101 feet. Humboldt visited and examined this work in 1804, and found the width of the channel at the bottom to be from 9 to 13 feet, with side slopes from 40 to 45 degrees. Such work accomplished at that age of imperfect appliances was truly wonderful and may well bo compared with the Suez or any other canal work of the present day.