90 Prof. Tyndall on the Absorption and Radiation 



determinations are not very wide of the truth. Irregularities, 

 however, are revealed. Some remarkable ones occur in the case 

 of carbonic acid, with the chambers 23*8 and 25*6, — the absorp- 

 tions in the first chamber varying in this instance from 11*7 to 

 10*4, and in the second chamber from 11*4 to LOS, and in both 

 chambers from 13" 1 to 12*0. The gas which gave the largest 

 of these results was generated from marble and hydrochloric 

 acid ; the next was obtained from chalk and sulphuric acid, and 

 the gas which gave the smallest result was obtained from bicar- 

 bonate of soda and sulphuric acid. The slight differences accom- 

 panying these different modes of generation made themselves 

 felt in the manner recorded in the Table. 



Table VIII. — Nitrous Oxide. 

 Length. Absorption per 100. 



1st 2nd 1st 2nd Both 



chamber. chamber. chamber. chamber. chambers. 



2-8 46-6 16-1 32-9 33'9 



12-2 37-2 23-1 30-0 32'0 



15-4 34-0 236 29*6 32-0 



17-8 31-6 262 29-6 327 



The differences arising from different modes of generation are 

 most strikingly illustrated by the powerful gases. My friend 

 Dr. Frankland, for example, was kind enough to superintend for 

 me the formation of a large holder of oleriant gas by the so-called 

 " continuous process," in which the vapour of alcohol is led 

 through sulphuric acid diluted with its own volume of water ; 

 the following results were obtained : — 





Table 



IX. — Olefiant Gas. 





Len 



gth. 





Absorption per 



100. 



1st 



2nd 



r 

 1st 



2nd 



Both 



chamber. 



chamber. 



chamber. 



chamber. 



chambers. 



2-8 



46-6 



34-6 



66-1 



67-7 



8-0 



41-4 



44-2 



65-3 



67*5 



15-4 



340 



536 



62-3 



67-0 



Considering the difficulty of the experiments, the agreement 

 of the absorption of both chambers, the sum of which was the 

 constant quantity of 49*4 inches, must be regarded as satisfac- 

 tory. This is the general character of the results as long as we 

 adhere to the same gas. Olefiant gas generated by mixing the 

 liquid alcohol with sulphuric acid and applying heat to the mix- 

 ture, gave the results recorded in the following Table : — 



