A simplified platinotype process

A SIXPLII;IEIJI'I.ATISoTSPl~hOCESS, just published by Captain Pizzighelh, by which prints are produced directly in the printing frame without subsequent development, has rendered that process one of the simplest printing processes, and may do much to bring it into competition with the silver This process, especially as it seems to afford either a glossy or matt surface. is accomplished by adding to the sensitizing solution some vehicular substance, in practice gum-arabic or arrow-root, which prevents the penetration of the paper by the solution, and at the same time some one of the usual developing agents, as ammonium or sodium ferric oxalate, together with the chloro-platinitc of potassium. Reduction of the platinum salt thus takes place in the printin, (I frame, and, as the picture becomes visible, the exposure can be judged as accurately as in the silver process, whilst all the subsequent operations of the silver process of washings, toning, fixing, etc., are rcplaccd by simple wnshin g, first in acidulated water and then in ordinary water for ten or fifteen minutes : which completes the process. The sheet rubber or waxed paper, to prevent effect of moisture, is also unnecessary. The prints may be underSeveral modifications in working are practicable. exposed and laid aside in the dark for several hours, to be brought up bp a continuating action which takes place, or they may be still more underexposed and be developed as usual. Time is wanting to permit definite statement as to the keeping qualities of the paper, but samples have remained unchanged for several weeks. C. F. H. 'I‘HE IDEIiTITY OF INOSITE AND I)AMl%OSE. Maquenne(B&, 48, r62).--In 1868, AimC Girard discovered among the products

SOL. cpii?i~,

of the action of hydriodic acid on the dambonite, obtained from crude Gaboon caoutchouc, a saccharine substance having the composition c” H” O”, to which he gave the name clambose. The properties of this substance closely resembling those of inosite, of which the preparation from walnut leaves and the constitution had been studied by the author (this JOURNAL, cxxiii, 498), the relations of The dambose was prethe two cornpounds suggested a closer investigation. pared by Girard’s method (Cb~~zptes L’LVUZ’ZVS, ii7, 820), and in its properties and those of its acetyl derivatives was found to be identical with inosite ; the latter substance, therefore, seems to be widely disseminated in vegetable Darnbonite is dimethyl inosite, and the name dambose must be organisms. of dambonite in abandoned for the sugar derived from it. The abundance Gaboon caoutchouc naturally suggests the latter substance as the most profitW. H. G. able source of inosite. ON,I NEW CLASS

OF VOI,T,~IC COMBINATIONS,

IN WHICH

OXIPIZABLE

Wright. in the con(Jour. Chem. .SOC.~-51, 672).- The author has made experiments struction of batteries in which platinum or carbon plates are immersed in comIn all cases, the municating fluids capable of undergoing chemical reaction. plate immersed in the oxidizable fluid acquires the lower potential, the other the higher potential. The liquids are prevented from mixing by the interposition of some other liquid, through which the two must diffuse, the intermediate METALS

AIW

REPLACEI~

BY ALTEKAL~LE

SOLUTIOXS.

C. R. Alder