1858.] DAUBENY — AMMONIA FROM VOLCANOS. 299 



to insist upon the fact, as supplying us with an argument from ana- 

 logy, that other bodies which are present in volcanos may, through a 

 similar reaction, be instrumental in bringing about the same result. 



It seems hardly possible that the affinity for nitrogen should be 

 confined to titanium alone ; and indeed I have pointed out, that 

 under different circumstances it may be proved to extend to several 

 of the commoner metals. 



Is it not, therefore, more probable, that in the interior of the 

 globe, where high pressure and other circumstances may modify the 

 nature of those reactions which take place under our eyes, nitrogen 

 combines directly with other bodies besides titanium — with iron for 

 instance, or possibly even with hydrogen ; and that it is in this 

 manner that that amount of ammonia which often finds its way through 

 the orifices of a volcano may be generated, seeing that its abundance 

 is often such as would lead us to doubt whether the nitride of a metal 

 comparatively so rare as titanium could alone afford it ; at least, if 

 the quantity found on the surface in such localities is to be regarded 

 as an index of the proportion which it bears to the other principles 

 present in the interior of the volcano 1 



P.S. — Since writing the above, my attention has been called by a 

 friend to a more recent paper by M. Ste.-Claire Deville, reported 

 upon in the ' Comptes Rendus,' which also I find given in extenso 

 in the January number of the ' Annales de Chimie ' for this year 

 1858. From this it appears that boron also, like titanium, has the 

 property of combining directly with the nitrogen of the air, and that 

 the compound which it forms with it possesses alike the property of 

 evolving ammonia under, the influence of the alkaline hydrates*. 



This fact is the more significant, from the occurrence of boracic 

 acid in the craters of certain volcanos, as in the iEolian Islands, 

 accompanied in this instance, as I have myself found, with muriate 

 of ammonia ; and, where the two are thus associated, we should not 

 be disposed to look for the source of the ammonia further than to 

 the nitride of boron generated within the interior of the volcano. 



Boracic acid, however, does not seem to be usually present in the 

 lavas of Vesuvius, for it has been only once observed amongst the 

 products of its eruptions, namely by Monticelli and Covelli in 1817. 

 I should, therefore, be unwilling to attribute the formation of ammo- 

 nia in this volcano generally to the agency of boron, and am rather 

 disposed to appeal to the fact as another proof that gaseous nitro- 

 gen, instead of that chemical indifference which has been commonly 

 attributed to it, possesses in fact a somewhat wide range of affinities, 



* The discovery of the compound of nitrogen and boron was made in 1841 by 

 Mr. Balmain, who, however, combined the two only by indirect methods. Mr. 

 Warington also in 1854 (Report Brit. Assoc. 1854, Sections, p. 76) pointed out 

 the existence of this very combination in the crater of the Island Volcano, sug- 

 gesting that the sal-ammoniac so abundant in that locality might be due to the 

 decomposition of the nitride by the action of steam. But the more recent re- 

 searches alluded to in my text first established that this nitride might be formed 

 by the direct union between boron and nitrogen. 



VOL. XIV. — PART I. X 



