288 MM. DevlUe and Le Blaac on the Gaseous Emanations 



analyses of the contents of three different tubes. The tempera- 

 ture of the sas varied between 207° and 210° F. : — 



Hvdrosulphuric acid . . . . 162 213 



Carbonic acid 92-(;8 87-67 



Oxygen 021 105 



Nitrogen + combustible gas 5'49 9*15 



100-00 100-00 



Mixture of the unabsorbablc 

 I, II. residues of the tubes 1. and 11. 



Nitrogen 5fi-75 



Hydrogen 18-81 



Protocarbonated 1 



1 A r 24-44 

 hydrogen. ... J 



10000 



H : C- H4 : : 1 : 077 

 Fearing that any small quantity of oxygen and aqueous vapour 

 which might have escaped the sulphuric acid would destroy a 

 portion of the hydrosulphuric acid in our tubes during their 

 transport, we determined this acid by precipitation on the spot, 

 as well as the carbonic acid. For this purpose we passed the 

 gas of the soffioni into an acid solution of acetate of lead, and 

 then successively into two bottles containing baryta water, and 

 ■weighed, in the one case the sulphuret converted into sulphate 

 of lead, and in the other the carbonate of baryta. This experi- 

 ment, twice repeated upon the lower soffione, furnished the fol- 

 lowing volumetric proportions : — 



Hydrosulphuric acid . . 6*4 5-1 



Carbonic acid .... 93-6 94-9 



The preceding analyses led to the following proportions : — 



Hydrosulphuric acid . . 4-3 3-9 2-0 



Carbonic acid . . . .95-7 96-1 98-0 



The comparison of these numbers shows, in the first place, 

 that the determination by precipitation furnishes for hydrosul- 

 phuric acid a higher number than the analysis of the gas col- 

 lected and preserved in the tubes : this might have been expected. 

 We may also conclude therefrom that the relative quantities of 

 carbonic acid appear to increase in proportion as we ascend to 

 a distance from the centre of the soffioni. 



It was interesting to learn whether the gas brought up by the 

 artesian borings presented the same composition. The following- 

 arc the numbers which we have obtained — temperature of the 

 gas 207° to 209° F. :— 



Hydrosiilpbmic acid .... 195 1'6 



Carbonic acid 9280 837 



Oxygen 0-66 22 



Nitrogen + combustible gas 4-59 125 



100-00 1000 



Mixture of the two unabsorbable 

 resiuues. 



Nitrogen 64-/5 



Hydrogen 18-24 



Protocarbonated 



hydrogen 



.atedj J7.01 



10000 

 H:C3H4:: 1:0-93 

 Lastly, in the upper part of the valley of the Possera, 

 beyond the limits of the soffioni made use of, two localities 

 of emanation occur which are very singular, inasmuch as they 



