224 Scientific Intelligence — Geology. 



5. On the Increase of Temperature in the interior of the Earth. 

 — M. Arago has lately communicated to the Academy of Sciences 

 the result of the thermometrical observations which he made on 

 the first of May last in the well which is now being sunk at the 

 slaughter-house (Abattoir) of Grenelle. The boring has now 

 reached the depth of 1312 English feet. The bed of chalk, 

 in which they have for so long been engaged, is not yet tra- 

 versed, but the numerous flints, which were unceasingly met 

 with at lesser depths, have now disappeared. The city of Paris 

 has determined that the boring shall continue to the depth of 

 2295 English feet, if the spouting water be not found sooner. 

 It is presumed that the water which will issue from so great a 

 depth will possess a temperature of between 93°2 and 95° Fahr., 

 and, in that case, it might be employed for hot-baths, &c. But 

 however this may be, we shall now adduce the thermometri- 

 cal observations which have been made at the depth of 1312 

 Enghsh feet. On the 29th of April, at 7 p. m., four instruments 

 were sent down, viz. two of M. Bunten's self-registering ther- 

 mometers, one a diversement thermometer which M. Magus of 

 Berhn had recently sent to M. Dulong, and another of the same 

 construction manufactured by M. Walferdin. The two first 

 were contained in a copper tube, in which they were secure from 

 the pressure of water ; the third was open at the top, but in 

 such a manner that the pressure could not alter its form ; and 

 the fourth was enclosed in a glass tube, which was hermetically 

 sealed. These four instruments, after having remained for about 

 thirty-six hours in the well or bore, were removed from it on the 

 first of May about 7 a. M. ; they then indicated the following 

 temperatures : — 



The first thermometrographe of M. Buten, . . 74 ".S 

 The second, do. . . 74'.21 



M. Magus' thermometer, a diversement, . . 74 ".30 



M. Walferdin's do. 74''.66 



Assuming, then, 74°.3 Fahr. as the temperature at the depth of 

 1312 English feet, if you subtract from this number that of 

 51°.08 Fahr., which indicates the mean temperature of the sur- 

 face of the earth at Paris, 23°.22 will remain for the increase 

 of temperature, corresponding to 1312 English feet of depth, 



