Notices respecting New Books. 231 



" The strata around Paris are in a general way very similar to 

 those forming and surrounding the London Basin (as it is often 

 termed), with which many of you are familiar. Its highest memhers 

 are composed of tertiary strata, of sand and calcareous sandstone, 

 beneath which are beds of mottled clay. The chalk on which this 

 lies is 1477 feet thick, resting on 150 feet of greensand, which in its 

 turn lies on the gault. This last is for the most part composed of 

 clay, and nearly impermeable to water. The whole, over a width of 

 many miles, is arranged in the form of what geologists call a basin ; 

 that is to say, the strata from their outcrops have a tendency to 

 slope towards a general centre, where for a space they lie more or 

 less horizontally. 



" On the margin of the basin, strata of greensand and gault rise 

 to the surface at heights in many places approaching to 330 feet 

 above the sea, Grenelle being only about 100 feet above that level. 

 Geologists knew that the water which fell on these strata at their 

 outcrop would of necessity percolate in the direction of the inclina- 

 tion of the beds ; so that at the lower points of the curvature a great 

 body of water must exist, confined, as it were, in a sponge, and un- 

 able to escape below, because of the impermeable quality of the beds 

 on which the porous strata rest. This deep-seated reservoir being 

 tapped by boring, the water would rise to the surface in the manner 

 I have explained. 



"In 1832 the municipal corporation of Paris, impressed with the 

 sanitary necessity of further supplies of water, voted 18,000 francs 

 for the construction of three artesian wells, a sum so ridiculously 

 small that the project was immediately abandoned. M. Mulot, 

 however, one of their engineers, having previously sunk in the chalk 

 at Suresne, at Chartres, and at Laon, to the depth of 1082 feet, 

 proved that it would be necessary to bore completely through that 

 formation to obtain a sufficient supply. This conclusion, based on 

 strict geological reasoning, was confirmed by MM. Arago and Wal- 

 ferdin, and in November 1833 the work was begun. With infinite 

 energy, skill and perseverance, M. Mulot carried it on, overcoming 

 every opposition, physical and moral; for he had not only to con- 

 quer those natural difficulties which beset so unexampled an under- 

 taking, but he had also to contend with municipal parsimony, that 

 shrunk from the continuance of supplying funds for a project based 

 on purely theoretical grounds. When he reached the depth of 1640 

 feet, at an expense of 263,000 francs, they stopped those supplies ; 

 but so great was the faith of M. Mulot in the correctness of the 

 principle involved, that he determined to continue the work at his 

 own charges. On the 26th of February 1841, the borer fell suddenly 

 several yards; and immediately, from a depth of 1800 feet, there 

 sprang from the orifice a huge column of water, cold at first but 

 warm afterwards. It now steadily yields more than 740,000 gallons 

 u-day. At the first burst the Supply was greater." 



Thirdly and lastly, we take up the lecture of Dr. Percy, the pro- 

 duction, if we mistake hot, of a mind differently constituted from 

 cither of the former. Pounds, shillings, and pence constitute the 



