M. Acbille Cazin on Internal Work in Gases, 



205 



it would follow that there would be nearly the same excess of 

 heat given off by the sides. 



As to the depression, it seems to diminish more rapidly than 

 the pressure p lt which also confirms the opinion advanced with 

 respect to one of its causes. By diminishing p Y we diminish the 

 velocities acquired during the expansion, and with them the tem- 

 porary diminution of pressure which the gas undergoes. 



The same results have been obtained by the comparison of 

 several other series observed at various times and under different 

 arrangements. I shall mention a few of them. 



Series XI. (September 1867). 

 Dry hydrogen. Metal reservoir B. 

 /? 1 = 2 , 70 atmospheres, ^2=0*52 atmosphere. Temperature 20°. 



("0=0*10 



[ h=—6 mm 



*=21 



5-6 



8-4 



11-3 



16-2 



25 







60 



-63 



-4 



+ 16 



+ 19 



+ 11 



+4 











r 0=o-]9 



U=+3 



2-3 



5-4 



7-7 



11 



17 2 



25 



50 





60 



-60 



-10 



+ 10 



+ 17 



+ 10 



+ 4 



+ 1 









r 0=o-2o 



\h= -2 



2-3 



4-8 



6-2 



8-5 



10-6 



151 



19-6 



25 



60 



-65 



-22 



-2 



+ 13 



+ 18 



+ 13 



+ 8 



+5 







/ 0=0-34 

 \A= -5 



2-3 



51 



71 





10-4 



177 





25 



60 



-57 



-9 



+ 11 





+21 



+ 11 





+5 







f = 1-07 

 1 h= -4 



2-9 



5-8 



8-5 





10-7 



12-9 



20-2 



24 



60 



-45 



-3 



+ 17 



... 



+ 19 



+ 17 



+ 7 



+4 







This series must be compared with Series VII., in which the 

 excess of pressure was nearly doable ; the maximum of depression 

 was also nearly double ; finally the line X X cuts the ^-axis 

 nearer the origin in the series where the value of p x is the least. 



I shall mention also a series on air, with the glass reservoir 

 and a water-manometer with a spherical enlargement; we shall 

 be able to compare it with Series IV. performed under the same 

 conditions, but with an excess of pressure Pi—p 2 nearly double, 



Series XII. (May 1867). 



Dry air. Glass reservoir B. Water-manometer with a sphe- 

 rical enlargement. 



p x = 2"76 atmospheres, jo 2 =0-73atmosphere. Temperature = 14°. 



f0 = O s -12 

 J£ = () mm 



t=... 



4-6 



9-3 



12-4 



21 





120 



+ 10 



-19 



-3 



+2 



+ 7 



. .. 







J0=O-12 



U=o 





4-6 



8 



12-3 



18 



20 



120 



+9 



-23 



-11 



+ 1 



+ 4 



+5 







J0 = O-16 





52 



11-4 



19-2 



... 



24 



120 



+ii 



-14 



-3 



+ 7 





+8 







/ = 0-20 





5 



11 



20 







120 



+ 16 



-8 



+8 



+ 12 



... 



... 







