M. Achille Cazin on Internal Work in Gases. 



209 



whence 



l + a(t + 8t) 



P 



a^=283^ = l°-5. 



Until the gaseous mass has reached this state, its various parts 

 are not of the same temperature, and consequently it is impos- 

 sible to deduce from the pressure observed the thermometric 

 state of the gas. We can only estimate what must have been 

 the temperature of the whole mass for its pressure to be that 

 which we observed at a certain period. For example, as h=0 

 for 5 seconds with hydrogen, we may admit that all the velocities 

 are extinguished after 5 seconds, and we then see in fig. 7 that 

 h= —40 millims. with carbonic acid, equivalent to 8p = — 5 mil- 

 lims. of mercury. The preceding formula gives 67= — 1*8. The 

 excess of pressure p^—p' was 2*85 atmospheres. This estimation 

 is evidently uncertain, and can only give a notion of the order of 

 magnitude of the effects produced. 



I have made a series of experiments on protoxide of nitrogen 

 with the glass reservoir. This series should be compared with 

 Series II. (hydrogen). 



Series XIII. (August 1867). 



Protoxide of nitrogen. Glass reservoir B. 



£> 1 = 3*95 atmospheres, ^2=0*49 atmosphere. Temperature 

 between 20° and 23°. 



r = 0-4 



A ' \^=-18 mm 



rf = 5-9 



11-7 



15-8 



19-5 



24 



54 



84 



120 



-48 



-33 



-18 



-7 



+ 1 



+8 



+3 







B-{^ 9 



6-3 



106 



139 



17 2 



221 



24 



39 



120 



-44 



-33 



-23 



-12 



-2 







+5 







r J = 0-52 



c 'U=-i 



6-9 



12-2 



17 



211 



241 



54 



84 



120 



-43 



-26 



-10 







+3 



+7 



+2 







D 1-0=052 



6-9 



121 



15-5 



20 



26 



41 



86 



120 



-43 



-29 



-19 



-8 







+5 



+2 







v f = 0-64 

 L 'JA=+19 



7 



111 



16-7 



21 



25 



41 





120 



-40 



-29 



-19 



-8 



— 1 



+ 4 



... 







v f = 0-97 



73 



12-6 



16-6 



21-2 



23-7 



54 



84 



120 



-31 



-23 



-12 



-2 







+ 8 



+3 







lj '"U=+20 



7-8 



125 



16-9 



23 



38 





... 



120 



-30 



-21 



-10 







+5 











„ J = 2-9 

 H **U=+14 



91 



14-2 



191 



22 



52 





82 



120 



-23 



-11 



-1 



+ 4 



+ 8 



... 



+ 1 







T r0 = 6-3 

 L *U=+4 



9-1 



12-5 



172 



221 



27 



57 





120 



-19 



-10 







+5 



+ 7 



+5 



... 







The curves XX of Series II. (hydrogen) and XIII. (protoxide 

 of nitrogen) are traced in fig. 8. They meet the axis of the 

 abscissae in the points #=6 seconds and #=16 seconds, or 



