﻿248 Intelligence and Miscellaneous Articles. 



the observations were most carefully made, and some of them were 

 repeated by Messrs. Cagnato and Strapazzon. 



The result arrived at by me is considered incorrect by Messrs. 

 Ramsay and Young — that " the vapour-pressure at a given tempe- 

 rature depends on the relative volumes of liquid and gas,'' because 

 it is "absolutely opposed"' to their experiments, and they thus 

 maintain that my liquids must have contained some other liquid, 

 or that they contained a permauent gas. 



But I reply that the memoirs which describe my experiments 

 detail all the minute care taken by me in order to obtain pure 

 liquids ; and they also give the calculation (in the case of ether 

 and of carbonic sulphide) which shows that the increase of pressure 

 could not be attributed to gas which might casually have remained 

 in the experimental globe. 



I would rather observe that, in order to observe such a pheno- 

 menon, an apparatus is necessary which enables us — as in my 

 case — slowly to compress the vapour, and to maintain it for a 

 time under constant pressure. 



ON THE FOBMATION OF FLOATING METAL LAMINA. 

 BY F. HYLIC S AND 0. FBOMM. 



The following are the results of this investigation : — 



1. Oxidizable metals such as zinc, iron, cobalt, cadmium, copper, 

 silver, and antimony, have the property that when separated by 

 electrolysis they float on the surface of solutions of their salts in 

 coherent laminae. 



2. This diffusion depends on two circumstances — firstly, the 

 presence of an impurity which does not mix with water; and, 

 secondly, the chemical action of the oxygen present. The same 

 effect is produced by sulphur on the halogens. 



3. For the spreading of the metals on the boundary of two 

 media, the thickness of the oily layer is not of essential importance. 



4. The form of the bounding surface has no appreciable influence 

 on the phenomenon : hence the spreading occurs even when one 

 medium is in the form of drops. 



5. Oxides and sulphides which conduct the current have the 

 property of spreading out on the bounding surface ; thus, for 

 instance, the lower degrees of oxidation of silver and of cadmium, 

 peroxide of lead, subsulphide of copper. 



6. The growth of the floating laminae is influenced by the 

 capillary attractions which those parts of the liquid experience 

 from which the precipitate is deposited. 



7. During the passage of the current a tension is often observed 

 which disappears when the current is broken, and apparently 

 depends on the difference of potential, like the surface-tension of 

 mercury when it is polarized. — Wiedemann's A nnalen, No. 4, 1894. 



