CHEMICAL SCIENCE. 201 



If we carefully make the analytical experiments, on exactly the same 

 portion of fresh bone, by both these methods, we do not arrive at correspond- 

 ing results ; and it will thus appear, that neither of these courses Avill bear 

 criticism. As this part of the subject will be presented to the Society in 

 connection with the evidence, it may be remai-ked now, that the kind of 

 information such results afford, is like that we obtain respecting the salts 

 existing in vegetable productions, when we analyze their ashes, instead of 

 confining our trials to the tissues and cell walls. 



In the analyses of osseous tissue which have been made since my commu- 

 nication to the Society, the simple process of decomposition in water has 

 been continued in application. As before observed, the bones readily impart 

 their earthy part to this fluid, both before and after the cartilage becomes 

 changed, in the act of decomposing into simpler forms of matter. Thus 

 far, the results have accorded with those of earlier trials, showing that in 

 the osseous tissue, bi-basic phosphate of lime may exist, and that the pres- 

 ence of mono-basic phosphate is not inconsistent with a neutral condition in 

 the tissues. It remains to be proved that protein, as well as water, may act 

 as a constitutional element equivalent to a base, in connection with lime, to 

 form double phosphates ; and we shall then have a simple and consistent 

 explanation of the fact of the existence of mono and bi-basic phosphates, 

 as now found in the secretions both healthy and morbid. 



ON THE EVOLUTION OF AMMONIA FROM VOLCANOES. 



Dr. Daubeny, in a recent communication to the London Geological Soci- 

 ety on the above subject, referred to the existence of a chemical compound 

 of titanium with nitrogen, known from the researches of Wohler and Rose ; 

 and pointed out its bearing on one part of the theory of volcanoes namely, 

 the evolution of ammonia, and the consequent presence of ammoniacal salts 

 amongst the products of their operations. He then commented on the hy- 

 potheses already suggested by Bischoff and Bunsen, to account for the vol- 

 canic production of ammonia viz., 1st, the decomposition of carbonaceous 

 or other organic substances ; 2ndly, the conversion, by the hot lava overflow- 

 ing the herbage, of the nitrogenized matter present in the latter into ammo- 

 nia, and the combination of this with the muriatic acid in the lava, giving 

 rise to the sublimation of sal-ammoniac. To both of these hypotheses the 

 author pointed out serious objections. He had himself proposed to account 

 for the presence of ammonia in volcanic outbursts by assuming that the 

 gaseous hydrogen, although incapable of combining with nitrogen under 

 ordinary pressures, might unite with it under that exercised upon it in the 

 interior of the earth ; and he still believes this idea to be worthy of consid- 

 eration, though, perhaps, it is impracticable to secure by experiment the 

 conditions necessary for the chemical union of these two gases. The affin- 

 ity, however, which certain metals possess for nitrogen, seems to afford more 

 solid grounds on which to build a theory respecting the production of am- 

 monia. Titanium has been found, by MM. Wohler and St. Claire Deville, to 

 absorb nitrogen from the air; and the union of heated titanic acid with ni- 

 trogen (forming a nitride of the metal) takes place, indeed, with so much 

 energy as to generate light and heat ; and thus constitutes a genuine case of 

 combustion, in which nitrogen, and not oxygen, acts as the supporter. Al- 

 l^pugh titanium is evidently present to some extent in most volcanoes, the 

 author is not disposed to think that it abounds sufficiently to account for 



