THEORY OF THE COMBINATION OF OXYGEN AND HYDROGEN BY PLATINA. 63 



is able also to extend liquids and solids in concrete laminae over the surface of the 

 acting solid body, and consists in a repulsion, which is developed from the parts of the 

 solid body by the simple fact of attenuation, and is highest when the attenuation is 

 most complete. The force has a progressive development, and acts most powerfully, 

 or at first, in the direction in which the dimensions of the attenuated mass decrease, 

 and then in the direction of the angles or corners which from any cause may exist on 

 the surface. This force not only causes spontaneous diffusion of gases and other 

 substances over the surface, but is considered as very elementary in its nature, and 

 competent to account for all the phenomena of capillarity, chemical affinity, attraction 

 of aggregation, rarefaction, ebullition, volatilization, explosion, and other thermome- 

 tric effects, as well as inflammation, detonation, &c. &c. It is considered as a form 

 of heat, to which the term native caloric is given, and is still further viewed as the 

 principle of the two electricities and the two magnetisms. 



615. I have been the more anxious to give a correct abstract of Dr. Fusinieri's view, 

 both because I cannot form a distinct idea of the power to which he refers the pheno- 

 mena, and because of my imperfect knowledge of the language in which the memoir 

 is written. I would therefore beg to refer those who pursue the subject to the me- 

 moir itself. 



616. Not feeling, however, that the problem has yet been solved, I venture to give 

 the view which seems to me sufficient, upon known principles, to account for the effect. 



617- It may be observed of this action, that, with regard to platina, it cannot be 

 due to any peculiar, temporary condition, either of an electric or of any other nature : 

 the activity of plates rendered either positive or negative by the pole, or cleaned with 

 such different substances as acids, alkalies, or water ; charcoal, emery, ashes, or glass; 

 or merely heated, is sufficient to negative such an opinion. Neither does it depend 

 upon the spongy and porous, or upon the compact and burnished, or upon the massive 

 or the attenuated state of the metal, for in any of these states it may be rendered 

 effective, or its action may be taken away. The only essential condition appears to be 

 a perfect^ clean and metallic surface, for whenever that is provided the platina acts, 

 whatever its form and condition in other respects may be ; and though variations in 

 the latter points will very much affect the rapidity, and therefore the visible appear- 

 ances and secondary effects, of the action, i. e. the ignition of the metal and the 

 inflammation of the gases, they, even in their most favourable state, cannot produce 

 any effect unless the condition of a clean, pure, metallic surface be also fulfilled. 



618. The effect is evidently produced by most, if not all, solid bodies, weakly per- 

 haps by many of them, but rising to a high degree in platina. Dulong and Thenard 

 have very philosophically extended our knowledge of the property to its possession by 

 all the metals, and by earths, glass, stones, &c. (611.) ; and every idea of its being 

 a known and recognised electric action is in this way removed. 



619. All the phenomena connected with this subject press upon my mind the con- 

 viction that the effects in question are entirely incidental and of a secondary nature ; 



MDCCCXXXIV. K 



