THERMAL WATERS OF ASIA MINOR. 107 



atmosphere, its origin has been sought for elsewhere, but 

 without success, and I am constrained to believe that nitrogen 

 is one of those elements stored up in the interior of the earth, 

 in more or less abundance, either pure or combined, and fre- 

 quently finds its way to the surface through those fissures by 

 which mineral waters are conducted. Its more frequent occur- 

 rence with thermal waters is doubtless owing to the greater 

 depth from which the latter come. 



After all, however, that has been said, we must acknowledge 

 the explanation imperfect, and as only furnishing another evi- 

 dence of the difficulty of learning any thing of the origin or 

 uses of this singular substance, nitrogen, in its elementary state. 



ON THE ANALYSIS OF THESE WATERS, PARTICULARLY WITH REFER- 

 ENCE TO THE SILICA AND ALKALIES. 



The general method of analysis adopted differed but little 

 from that usually employed, and the construction of the salts 

 out of the acids and bases has been made entirely from the 

 dictates of my judgment in the matter. 



The examination of the silica attracted considerable atten- 

 tion, from the fact that we are in the habit of always estimating 

 it as uncombined silica, even when found in alkaline waters. 

 Although my researches are sufficient to prove to my mind the 

 inaccuracy of this, still I have not thought proper in this paper 

 to deviate from the rule generally adopted, leaving it to more 

 extended research to decide the point. 



In the analysis of the waters of Broosa, nearly all of which 

 are alkaline, the following fact has been observed : that on 

 concentrating a considerable quantity of the water to a small 

 bulk all the carbonate of lime is precipitated and a portion 

 of the silica (whether in combination with lime or not is not 

 yet decided) ; but a large portion of the same still remains in 

 solution, as well as some lime, although the water is alkaline 

 with an excess of carbonate of soda. The silica is in such quan- 

 tity that it could remain only in solution in combination with 

 an alkali ; in fact, there is a silicate of soda and lime present. 



The question here arises whether the silica was in a state 

 of combination before the water was concentrated, or is it a 

 result that has taken place during the evaporation ; this ques- 

 tion can only be decided by more extended investigation. 



