TRANSACTIONS OF SECTION B. 613 



The third part contains suggestions as to the lines on which one must work to 

 obtain knowledge as to the best means of precipitation, with a view to subsequent 

 utilisation. 



12. The Beaction of Glycerides with Alcoholic Potash. 

 By A. H. Allen, F.G.S. 



13. Note on the Electrolysis of Alloys. By Henry C. Jenkins, 

 Assoc.M.Inst.O.I<:., F.G.S. 



The importance of the question as to whether alloys are capable of being 

 electrolysed has for a long time been recognised, and has already been under tho 

 notice of a Committee of this Association. Several experimenters have 

 endeavoured to separate the constituents of some alloys by this means, but 

 hitherto no success in this direction has been recorded. 



Doubtless one reason of this negative result may be found in the difficulty of 

 submitting a metallic bath to a sufficiently large difference of potential, owing to 

 its very low resistance ; but from the same cause there is another reason why 

 electrolysis should not take place, at least in the case of the majority of alloys, a 

 reason to which prominence does not hitherto seem to have been given. 



The variable polarisation, and the resistance of electrolytic baths generally, have 

 led to the adoption of the view that in an electrolytic bath the electricity is con- 

 veyed by some method of convection or of successive molecular discharge, 

 streams or chains of molecules carrying electrical charges from one electrode to 

 the other. The bath itself is formed of some body whose resistance when pure 

 is extremely high, so that it is usually necessary to add another body to it, an 

 impurity, which probably acts by increasing the number of free molecules present. 

 It is easy to imagine that in such an insulating medium molecules can be charged 

 with electricity, which charge they can retain until they reach some body having 

 a different potential to their own. But free molecules could not retain any 

 charge if entirely within a conducting envelope, and in contact with it ; and 

 although the possibility of the possession of a gaseous envelope by the molecules 

 forming a liquid has been recognised, still the conductivity of pure molten metals 

 is scarcely in favour of any view that there is insulation between their molecules. 

 If there were any considerable insulation it is difficult to account for the effects 

 upon electrolytes of very small electro-motive forces, and it will be thus seen 

 from these considerations that the want of success in the attempts to electrolyse 

 alloys still leaves quite open the question of their constitution, whilst it is in full 

 accordance with the conditions of Electrical Potential expressed by Laplace's 

 equation. 



From the fact that alloys in many cases form true compounds, which may he 

 obtained in a crystalline form if proper conditions are chosen, and because the 

 conditions as to temperature of an electrolytic bath may be those most favourable 

 for the precipitation of such a compound out of solution, it follows that all 

 future electrolytic experiments with alloys should be made at temperatures 

 sufficiently high to fuse any possible compounds, otherwise very deceptive results 

 would be obtained, owing to the difficulty of correctly sampling the bath. 



