M. E. Wiedemann on the Specific Heats of Gases. 101 

 Table II. -Experiments between 200° and 27°. 



W 



G 

 B 

 P 

 X 

 n 

 a 



T 



T 



m 



T, 



m l 



h 



a. 

 



o 1 

 t 



M 

 9 

 G 



60-81 



7-93 



752-88 



57-52 



20*4 



3-40 



20-75 



2086 

 0184 



32-60 

 0014 

 0-172 

 0-0134 



10-83 



10-65 



27-08 

 1975 

 170-4 

 0-4195 



2, 



59-85 

 7-55 



752-88 

 46-92 

 20-8 



2£ 



33 

 20-55 

 19-7 



017 

 30-67 



0028 



0-159 



0013 

 10-22 

 1002 

 25-4 

 200-2 

 174-8 



0-4267 



3. 



60-65 



7-24 

 752-88 

 46-5 

 21-2 



2 



3f?2 

 21-35 

 21-05 



0-164 

 3210 



00166 



0-158 



00133 



10-3 



1013 



26-85 



20325 



176-4 



0-4286 



4, 



60-43 

 5-98 



752-88 

 45-7 

 21-6 



If 

 3-42 



21-85 



2315 

 017 



32-77 

 0-006 

 0192 

 0017 

 8-75 

 8-61 



28-35 

 204-75 

 176-4 

 0-4401 



6075 



8-06 

 748-3 

 47-4 

 21-8 



2 lr 



372 

 22 

 21-25 



014 

 32-53 

 -0-005 



0-130 



0-0129 



10-74 



10-59 



2715 



195-4 



168-25 



0-4251 



6. 



60-9 



7-22 

 748-3 

 48-1 

 22-4 



2 



3-61 

 22-6 

 21-36 



0133 

 31-96 

 -00025 



0-118 



0-0128 

 10-1 



9-98 

 26-86 

 200 

 173-14 



0-4361 



The mean value is 0*4293 ; the greatest deviation therefrom 

 0-0108. 



The order of experiments was 1, 2, 3, 4, la, 2a, 3a, 5, 6, 

 7, 4 a, 5 a, 8, 6 a. The number 0*4293 does not differ very- 

 much from that obtained by Regnault, viz. 0*404 (mean of 

 0*4147 and 0*3933). Regnault did not carry out experiments 

 between 100° and 20°. 



Ethylene, like carbonic acid and nitrous oxide, shows a con- 

 siderable change in specific heat for changes of temperature. 

 The following true specific heats are calculated : — 



For 6 0*3364 



100 0*4189 



200 . ... . 0*5015 

 Multiplying by the specific gravity of ethylene (0*9672) we 

 obtain the relative heats : — 



For 100 0-3254 



150 0*405 



200 0*4851 



Nitrous Oxide- 

 The gas was prepared by long-continued heating of ammo- 

 nium nitrate free from chloride and nitrite ; it was purified by 

 passage through caustic potash (to absorb ammonium nitrate 

 carried over and nitric acid) and through sulphuric acid (to 

 absorb free ammonia). 



