( 143 .) 



Progressive Increase of Temperature as we descend in the Crust 

 of the Earth. 



For the purpose of ascertaining whether a constant stream of 

 M-ater could be obtained by means of an artesian well, sunk on 

 the south side of the Jura mountains, at the distance of about a 

 league from Geneva, and at an elevation of 297 feet above the 

 level of the lake, M. Giroud, at his country residence at Pregny, 

 bored to the depth of 547 feet without success. Despairing of 

 success, he offered great facilities to any persons who might wish 

 to prosecute the enterprlze, for the purpose of scientific inquiry. 



On this occasion AIM. Aug. De la Rive and F. Marcet 

 made a successful application to the friends of science, and also 

 to the government, and funds were obtained sufficient to enable 

 them to continue the operations during eight months, and to 

 extend the boring to the depth of 682 feet. The hole bored 

 was about four and a half inches in diameter. Water began to 

 appear in it at the depth of twenty feet, and it is worthy of re- 

 mark, that the height at which the water stood in the opening, 

 as measured from the surface, was lower when the greatest depth 

 was obtained, than it was at half the depth. At 275 feet of 

 depth, the water stood at 14 feet from the surface ; at 500 feet 

 it sunk to 22 feet 5 at 550 feet, to 35 feet. It then rose. At 

 595 feet. It stood at 24 feet 6 Inches, but at 675 feet, it again 

 sunk to 35 feet 8 inches. The result of this praiseworthy effort 

 must operate as a salutary preventive from any farther expen- 

 sive attempts to obtain running fountains from the theory of an 

 internal communication with the springs on the summits of the 

 Jura. 



Having attained the extraordinaiy depth above mentioned, 

 the experimenter devised the means of ascertaining the tempera- 

 ture of this opening at different depths. As the common ther- 

 mometer would not answer the purpose, they contrived a self- 

 registering thermometer, constructed on a large scale, and whose 

 accuracy was subject to the most satisfactory tests. 



