AETESIAN WELLS HT THE DESERT. 465 



These wells, however, are too few and too scanty in supply 

 to serve any other purposes than the domestic wells of other 

 countries, and it is but recently that the transformation of desert 

 into cultivable land by this means has been seriously attempted. 



minutes and five seconds and another of five minutes and fifty-five seconds. 

 The shortest of these periods is longer than the best pearl-diver can remain 

 below the surface of salt water. The wells of the Sahara are from twenty to 

 eighty metres deep. — Desor, La Forit Vierge et Le Sahara. 



The ancient Egyptians were acquainted with the art of boring artesian 

 wells. Ayme, a French engineer in the service of the Pacha of Egypt, found 

 several of these old wells, a few years ago, in the oases. They differed little 

 from modern artesian wells, but were provided with pear-shaped valves of 

 stone for closing them when water was not needed. "When freed from the sand 

 and rubbish with which they were choked, they flowed freely and threw up 

 fish large enough for the table. The fish were not blind, as cave-fish often 

 are, but were provided with eyes, and belonged to species common in the 

 Nile. The sand, too, brought up with them resembled that of the bed of that 

 river. Hence it is probable that they were carried to the oases by subterranean 

 channels from the Nile. — Desor, La Foret Vierge et Le Sahara ; Stoppani, 

 Corso di Oeologia, i., p. 281. Barth speaks of common wells in Northern Af- 

 rica from 200 to 360 feet deep. — Reisen in Africa, ii., p. 180. 



It is certain that artesian wells have been common in China from a very 

 remote antiquity, and the simple method used by the Chinese — where the 

 drill is raised lind let fall by a rope, instead of a rigid rod — has lately been 

 employed in Europe with advantage. Some of the Chinese wells are said to 

 be 3,000 feet deep ; that of Neusalzwerk in Silesia is 2,300. A weU was bored 

 at St. Louis, in Missouri, a few years ago, to supply a sugar refinery, to the 

 depth of 2,199 feet. This was executed by a private firm in three years, at 

 the expense of only $10,000. Some years since the boring was recommenced 

 in this well and reached a depth of 3,150 feet, but without a satisfactory 

 result. Another artesian well was sunk at Columbus, in Ohio, to the depth 

 of 2,500 feet, but without obtaining the desired supply of water. Perhaps, 

 however, the artesian well of the greatest depth ever executed until very 

 recently, is that bored within the last six or seven years, for the use of an 

 Insane Asylum near St. Louis. This well descends to the depth of three 

 thousand eight hundred and forty-three feet, but the water which it furnishes 

 is small in quantity and of a quality that can not be used for ordinary do- 

 mestic piu-poses. The bore has a diameter of six inches to the depth of 425 

 feet, and after that it is reduced to four inches. For about three thousand 

 feet the strata penetrated were of carboniferous and magnesian limestone alter- 

 nating with sandstone. The remainder of the well passes through igneous 

 rock. At St. Louis the Missouri and Mississippi Rivers are not more than 

 twenty miles distant from each other, and it is worthy of note that the waters 

 of neither of these two rivers appear to have opened for themselves a consid- 

 erable subterranean passage through the rocky strata of the peninsula which 

 separates them. 



Boring has been carried to a great depth at Sperenberg near Berlin, where 



