164 Intelligence and Miscellaneous Articles. 



Lozere, at the upper portion of the Valley of Palheres, which opens 

 near Yillefort. An examination of the district in question proved 

 the former existence of a glacier which was limited to the cirque 

 which enclosed it, and did not descend into the valley. A lateral 

 and a terminal moraine were found, and roches perchees were ob- 

 served on the sides of the valley. No striae or polished surfaces 

 were seen, owing to the schistose rocks being easily decomposed. 



XVIII. Intelligence and Miscellaneous, Articles. 



ON THE COMPRESSIBILITY OF LIQUIDS. 

 BY MM. AMAURY AND DESCAMPS. 



TN June 1868, in conjunction with M. Jamin, we laid before the 

 -V Academy a method for measuring the compressibility of liquids ; 

 since then M. Jamin has intrusted to us the task of continuing this 

 research. We have made a great number of determinations, the 

 results of which we have the honour to lay before the Academy. 

 The following Table gives the coefficients of compressibility for one 

 atmosphere : — 



Distilled water at . 15 C 00000457 



Alcohol 0-0000835 



Alcohol 15 0-0000911 



Ether 0000109 



Ether 14 0*000128 



Sulphide of carbon 14 0*0000635 



Mercury 15 0*00000187 



Solution of chloride of potassium, — 



Containing in 1000 of water 50 of KC1 0*0000419 



100 „ 0*0000388 



150 „ 0*0000556 



200 „ 0*0000332 



250 ...... 0*0000318 



300 „ ...... 00000306 



Water 00000457 



These coefficients have been deduced from experiments in which 

 the pressure varied from 1 to 10 atmospheres. 



We may observe that the coefficient 0*00000187 found for mer- 

 cury varies considerably from the coefficient 0*00000*295 which 

 Grassi obtained by the use of M. Regnault's method, while with the 

 more compressible liquids the agreement between our numbers and 

 those of M. Grassi is perfect. This difference arises from the cir- 

 cumstance that, as the compressibility of mercury is very small, the 

 least error in the measurement of the correction due to the change 

 of volume in the piezometer has a considerable influence on the true 

 coefficient, whereas with the more compressible liquids this source 

 of error is less apparent. 



The expansion of liquids, as is well known, gradually increases 

 with the temperature, and, when they reach the boiling-point, is vir- 

 tually equal to that of gases. We imagined it would be the same 

 with their coefficient of compressibility, and we made very accurate 

 experiments with water, alcohol, and ether from this point of view. 

 We measured the coefficient of compressibility under very feeble 



