76 Intelligence and Miscellaneous Articles, 



the Eocene and Miocene period, while a gradual transition occurred 

 between the Cretaceous and Eocene rocks. 



In the gypseous scries which overlies the flint conglomerate 

 several peculiar effects were noted, owing to the easy manner in 

 which tumbled and broken masses of gypsum are reconstructed by 

 partial solution and recrystallization when they have been removed 

 from their original position by the slipping of the underlying shales. 



The alluvial gravels of the Sinaitic valleys are generally similar 

 in containing a coarser and a finer material; the latter is the older, 

 and has apparently been deposited by comparatively slow-flowing 

 streams. In conclusion, the author called attention to the evidence 

 of lakes, marshes, and streams having formerly occupied what are 

 now dry barren valleys. 



X. Intelligence and Miscellaneous Articles, 



ON THE HEAT CONSUMED IN INTERNAL WORK WHEN A GAS DI- 

 LATES UNDER THE PRESSURE OF THE ATMOSPHERE. BY M. J. 

 MOUTIER. 



MCLAUSIUS has shown that the quantity of heat necessary to 

 • heat a body consists in general of three distinct parts : the first 

 represents the increase of the quantity of heat actually existing in the 

 interior of the body ; the second has for its equivalent the external 

 work, and the third the internal work. When a gas dilates under the 

 pressure of the atmosphere, the external work is easily estimated. If 

 we call d the density of the gas compared with the air, and a the coef- 

 ficient of dilatation of the gas under the pressure of the atmosphere, 

 the increase of volume experienced by 1 kilogramme of gas in passing 



from zero to 1° is, in cubic metres, -. Moreover the atmo- 



1-2932x8 

 spheric pressure upon one square metre is equal to 10333 kilogs. ; 

 consequently when 1 kilog. of gas dilates from zero to 1° under 

 the constant pressure of the atmosphere, the external work is equal 



to . — ; and the heat consumed in external work is obtained 



1-2932 x d 



by dividing this number by the mechanical equivalent of heat, 425. 



If we represent by C the specific heat of the gas under the pressure 



of the atmosphere, by K the absolute specific heat independent of 



the physical condition of the body according to M. Clausius, and by 



y the heat consumed in internal work, we have, when 1 kilog. of 



gas dilates by 1° under the pressure of the atmosphere, 



c 1 X 10333X* 



425 1-2932 X J 7 V ' 



This equation contains two unknown quantities, K and y. 



Messrs. William Thomson and Joule have succeeded in demon- 

 strating the existence of internal work in a gas which expands 

 without effecting any external work. The diminution of tempera- 

 ture which accompanies the flow of the gas allowed the calculation 

 of the proportion of the internal to the external work when the gas 



