714 REPORT—1899. 
but bromine is not decolorised by a solution of the acid in chloroform. Its 
behaviour, therefore, resembles that of isolauronolic acid, C,H,,0,, which melts at 
135°;1 the amide of isolauronolic acid, however, is described by Blanc” as melting 
at 129-130°, and the nitrile boils at 205° under 760 mm. 
The investigation of the amide and its behaviour on oxidation is being 
continued. 
8. The Action of Caustic Soda on Benzaldehyde. 
By Dr. C. A. Koun and Dr. W. Trantom. 
9. On the Action of Light upon Metallic Silver. 
By Colonel J. WarERHOUSE. 
Following on the lines of Moser’s thermographic observations, it may be asserted 
that pure silver is sensitive to light. If cut-out masks be laid upon the surface of 
silver leaf or foil, or on a daguerreotype plate, and exposed to the sun’s rays, a 
visible image uitimately becomes apparent on the metallic surface. The ettect, 
however, may be got in a very much shorter space of time if the exposed metal be 
subjected to mercury vapour or developed by immersion in an acid solution of a 
ferrous salt mixed with nitrate of silver. Clear images, hardly as yet to be called 
pictures, can thus be obtained of a permanent character, so that it may be possible 
to work the daguerreotype process without iodising the plate. In fact all photo- 
graphic phenomena, the invisible developable image, the visible image, reversal, 
and the effect of pressure marks, can be illustrated on the plain silver surface ; 
this, at least, is a new discovery. Copper also seems to be sensitive in the same 
way, and doubtless other metals. 
10. Some Experiments to obtain Definite Alloys, if possible, of Cad- 
mium, Zinc, and Magnesium with Platinum and Palladium. By 
Professor W. R. E. Hopexinson, Captain Warinc, £.A., and Captain 
Desporouen, £.A., Ordnance College, Woolwich. 
That platinum alloys with zinc has been noticed by several experimenters— 
Gmelin-Krant (8), 1193; Gehlen, Fox, Murray, &c., Deville and Debray, ‘ Ann. 
Chem. and Phys,’ (3), 56,430; Boussingault, ‘ Ann. Chem. and Phys.’ (3), 53, 429. 
Zine and Platinum.—it is generally stated that the metals unite with energy, 
and that when the combination is heated until infusible the compound is repre- 
sentable by Pt,Zn,. 
Deville and Debray, after treating the alloy of Pt and Zn with dilute sulphuric 
acid, obtained a black powder containing 31 per cent. zinc and a little free 
platinum. : 
The method employed has been to submit a weighed amount of platinum to 
the vapour of the volatile metal, maintaining the platinum or compound formed 
all the time at a temperature above the boiling-point of the particular volatile 
metal. 
Two plans have been tried: one carrying the vapour with hydrogen; another 
heating ina vacuum. A very infusible Jena glass tube was employed. 
In each case a weighed quantity of platinum ® (or palladium) was contained in 
a porcelain boat. Almost touching this was another boat containing the volatile 
metal in very considerable excess. The region about the two boats was heated 
very strongly in a powerful combustion furnace, and in the case where hydrogen 
was used the current of gas passed over the zinc (or other metal) towards the 
1 Koenigs and Hoerlin, Ber. 1893, xxvi. 811; W.H. Perkin, jun., Zrans. Chem. Soc. 
1898, lxxiii. 831. 
2 Compt. Rend. 1896, cxxili. 749. 
3 Very thin foil. 
