CONDITIONS OF NUCLEI, OF THE NASCENT STATE, ETC. 75 



any other liquid or solid substance ; as, for instance, mercury or platina, if they were 

 made to replace the water, i. e. if the view of independent action which I have taken 

 (626. 627.) as a consequence of Dalton's principles be correct. It would also seem 

 that the mutual relation of similar particles, and the indifference of dissimilar particles 

 which Dalton has established as a matter of fact amongst gases and vapours, extends 

 to a certain degree amongst solids and fluids, that is, when they are in relation by 

 contact with vapours, either of their own substance or of other bodies. But though 

 I view these points as of great importance with respect to the relations existing be- 

 tween different substances and their physical constitution in the solid, liquid, or 

 gaseous state, I have not sufficiently considered them to venture any strong opinions 

 or statements here. 



658. There are numerous well-known cases in which substances, such as oxygen 

 and hydrogen, act readily in their nascent state, and produce chemical changes which 

 they are not able to effect if once they have assumed the gaseous condition. Such 

 instances are very common at the poles of the voltaic pile, and are, I think, easily ac- 

 counted for, if it be considered that at the moment of separation of any such particle 

 it is entirely surrounded by other particles of a different kind with which it is in close 

 contact, and has not yet assumed those relations and conditions which it has in its 

 fully developed state, and which it can only assume by association with other particles 

 of its own kind. For, at the moment, its elasticity is absent, and it is in the same 

 relation to particles with which it is in contact, and for which it has an affinity, as the 

 particles of oxygen and hydrogen are to each other on the surface of clean platina 

 (626. 627.). 



659. The singular effects of retardation produced by very small quantities of some 

 gases, and not by large quantities of others (640. 645. 652.), if dependent upon any 

 relation of the added gas to the surface of the solid, will then probably be found imme- 

 diately connected with the curious phenomena which are presented by different gases 

 when passing through narrow tubes at low pressures, which I observed many years 

 ago*; and this action of surfaces must, I think, influence the highly interesting pheno- 

 mena of the diffusion of gases, at least in the form in which it has been experimented 

 upon by Mr. Graham in 1829 and 1831-}-, and also by Dr. Mitchell of Philadelphia J 

 in 1830. It seems very probable that if such a substance as spongy platina were used, 

 another law for the diffusion of gases under the circumstances would come out than 

 that obtained by the use of plaster of Paris. 



660. I intended to have followed this section by one on the secondary piles of 

 RiTTER, and the peculiar properties of the poles of the pile, or of metals through which 

 electricity has passed, which have been observed by Ritter, Van Marum, Yelin, 

 De la Rive, Marianini, Berzelius, and others. It appears to me that all these 



* Quarterly Journal of Science, 1819, vol. vii. p. 106. 



t Quarterly Journal of Science, vol. xxviii. p. 74., and Edinburgh Transactions, 1831. 

 X Journal of the Royal Institution for 1831, p. 101. 



l2 



