ANNIVERSARY ADDRESS OF THE PRESIDENT. CV11 



consideration, as it is evident that the volcano must be considered 

 the discharging flue of the subterranean laboratory, and therefore 

 the place where its gaseous products ought to be traced in their pas- 

 sage outwards. That ammoniacal compounds are found in the vicinity 

 of volcanic vents is well known ; but MM. Bischoff and Bunsen 

 have endeavoured to prove that the production of ammonia is due to 

 chemical action on the surface, and not within the crust of the earth, 

 as, for example, in the celebrated hypothesis, that the hot lava, 

 whilst overflowing the herbage, so far promotes its decomposition, as 

 to set free its nitrogen, which uniting with the muriatic acid of the 

 lava, became sublimed as sal-ammoniac. This theory, though in- 

 genious, is shown by Dr. Daubeny to be inapplicable to many vol- 

 canic districts, in which, though the herbage is far too scanty to sup- 

 ply a sufficiency of nitrogen, the sal-ammoniac is not less in quantity ; 

 he therefore adopts, as in his opinion more probable, the theory of the 

 formation of ammonia within the crust of the earth, and adduces, in 

 support of his explanation, the affinity which certain metals are known 

 to possess. For example, "Wohler and Rose have proved the exist- 

 ence of a compound of titanium with nitrogen ; and Wohler and Ste.- 

 Claire Deville have shown that titanium absorbs nitrogen even 

 from the air, and that heated titanic acid, when brought into con- 

 tact with nitrogen, leads to the production of a nitride of titanium 

 with so intense a chemical reaction as to generate light and heat, ni- 

 trogen in this case, instead of oxygen, acting as the supporter of com- 

 bustion. Dr. Daubeny also alludes to the recently discovered fact, to 

 which I shall again refer, that boron, like titanium, has the property of 

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

 thus formed possesses the property of evolving ammonia under the in- 

 fluence of the alkaline hydrates. Dr. Daubeny further observes that 

 we cannot fairly conclude, from the difficulty hitherto experienced in 

 producing a direct combination of nitrogen and hydrogen, that such 

 a combination would be impossible under the different circumstances 

 of pressure, heat, &c. which may be expected within the crust of the 

 earth : in fact, he considers that such circumstances might even be 

 sufficient to induce the combination of hydrogen and nitrogen, and 

 thus produce ammonia directly, although it has not been possible to 

 do so in the laboratory of the chemist. Titanium is present in most 

 volcanos, though Dr. Daubeny admits that it is not sufficiently 

 abundant to account for the large quantity of sal ammoniac known 

 to occur, and, I will add, for the continued production of it, unless, 

 indeed, it be assumed that the titanium discovered outside the vol- 

 canic vent, and freed from the nitrogen with which it may have been 

 combined, is only a small portion of that which has passed through 

 the chemical decomposition, and still remains below the crust. Such 

 a conclusion would not be unreasonable, as it is certainly quite con- 

 sistent with sound speculation to deduce what is passing out of sight 

 from that which can be actually observed. Boracic acid, however, 

 is sufficiently abundant in many volcanos to account for the produc- 

 tion of any amount of ammonia ; and it only remains in those cases 

 to determine whether the chemical reactions which have led to the 



