286 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Dec, 1904. 



able on account of its combination with metals in the 

 hidden depths. 



The occurrence of graphite offers many interesting 

 suggestions. In Siberia and in the Western Alps, beds 

 (if graphite may be traced into strata that retain 

 recognisable vegetable I'eniains. V\'einschenk ■ , who 

 has "given special :ittention to this matter in recent 

 years, believes that the graphitic anthracite of the 

 Alps — which one may see, for example, collected for 

 fuel on the summit of the Little St. Bernard — passes 

 into graphite as the result of the intrusion of the ad- 

 jacent granite. In the .-\rch;can region, however, of 

 the frontier of Bavaria and Bohemia, Weinschenkj 

 finds no sign of an organic origin for the beds and 

 lens-like masses associated with the ancient gneiss. 

 He urges that the graphite is here deposited from gase- 

 ous exhalations, whicli were connected with the inflow 

 of granite in the area. CirLuier's experiments on carbon 

 monoxide in 1869 lead \\'einschenk to reg;ird this gas 

 as a very probable source of carbon in the gneisses. 

 It appears that iron f)rcs at 300° C. decompose carbon 

 monoxide with deposition of graphite; the little known 

 metallic carbonyls, moreover, may also be looked to as 

 furnishing carbon in a volatile foi'm. Such substances, 

 with carbon dioxide and water, are pictured as 

 saturating the rocks in contact with the invading mass, 

 and as taking advantage of any planes of easy penetra- 

 tion, during the folding of the ancient series. Mica- 

 schists, with the easy partings offered by the prevalent 

 mineral, might thus become impregnated in a special 

 degree; while cavities provided by earth-movements 

 would ser\ e as chambers of deposition. As years go 

 on, we shall probably learn more and more of the pro- 

 ducts vet to emerge from the earth's unknown interior. 

 While we are on the verge of gaining some ideas on 

 elemental transmutation, we may e\'en look forward to 

 the exhalation in due time of substances imknown to us 

 in our present geological age. Time may be an im- 

 portant factor in the internal processes of our vital 

 globe; and who shall say that senility has yet set in? 

 Is it not at least a fair speculation that life itself m;iy 

 be a phenomenon expressing a particular phase in the 

 history of our globe? Life may not be a merelv 

 external reaction, limited by temperatiu-e, and con- 

 trolled by cosmic law upon a cooling and indifferent 

 planet. May w'e not in time see some return towards 

 the conception of the grc.it Karlh-mother, fostering 

 her children from within, stimulating them daily 

 against attack, revi\ing them, perhaps, in hours fif 

 danger, and fitting them to cope with future changes 

 bv changes in her own heart's core? 



" .Mihandlunfjen der k. baver Akademie der Wiereneclmftf n 

 II. CI, XXI. Band, irjno. 



I IhiJ , XIX Bnnd, i:-'.,;. 



AwaLrds to the Wellcome Chemical 

 ' [Research Laboratories, London. 



TuK Committee on .Awards of the Loufsiana Purchase Exposi- 

 tion, St. Loui?. have conferred upon the Wellcome Chemical 

 Research Laboratories the distinction of a grand prize and 

 three gold medals, in recognition of the importance and educa- 

 tional value of the chemical and phannacoKnostical researches 

 conducted in these lal)oratories under the direction of Dr. 

 Frederick B. Power. 



PKotogroLphy. 



Pure and Applied. 



By Ch.M'.m.w Jones, F.I.C, F.CS., &c. 



Koii/g's Thrce-Colpw Process. — This process, only re- 

 cently published, has attracted a good deal of attention, 

 and deservedly so, for it not only illustrates a new 

 principle as applied to the purpose of colour photo- 

 graphy, but has been worked out by its author to a 

 successful issue. Whether or not it will be found to 

 fulfil the conditions necessary to establish itself as a 

 standard or commercial process, only time can prove. 

 It is a triple film method, Isut differs from those previ- 

 ously proposed, in that each colour is printed out by 

 light. 



Many of the organic dye-stuffs yield on reduction 

 colourless or leuco-derivatives, which can be oxidized 

 to reproduce the original colour with more or less 

 facility, and expf)sure to light generally facilitates 

 this oxidation. By choosing a dye of a suitable colour, 

 and one that yields a leuco-derivative of sufiicient 

 stability to withstand the necessary operations and yet 

 is sensitive enough for practical printing- purposes, it 

 is obvious that the colour may be obtained directly by 

 exposure to light under the negative, and the necessity 

 for a relief produced by the chromated gelatine process, 

 or any similar indirect method of getting the required 

 distribution of the colour, is obviated. 



These leuco-derivatives were found to be useless by 

 themselves or in an inert film, as they then gave only 

 poor and flat images, but the presence of a nitric acid 

 ester was discovered to overcome this difficulty. 

 Pyroxylin being an ester of nitric acid a collodion film 

 is employed, and mannite nitrate is very suit.able for 

 further augmenting the sensitiveness. The removal of 

 the excess of the leuco-derivative after exposure was 

 at first a difficulty, as ordinary solvents and acids were 

 found useless for the purpose. But monochloracetic 

 acid is effective, and it is used as a ten per cent, solu- 

 tion. 



The process consists in coating a suitably surfaced 

 paper with a one-and-a-half per cent, collodion, to 

 which the leuco-derivative and other desirable materials 

 have been added, exposing under the appropriate nega- 

 tive until the colour is sufficiently intense, fixing in the 

 chloracetic ,-uid solution, washing, and dipping into a 

 gelatine solution that contains chrome alum and dry- 

 ing. The print is again dipped into the gelatine solu- 

 tion and dried to effectively protect the collodion film 

 during the application of the collodion th;it is to 

 furnish the second colour. This routine is repeated for 

 the second colour .and again for the third, and the print 

 is finally varnished. 



The method of judging when each colour is correctly 

 printed is not very clear, as it seems impossible to 

 adjust the depth of tint of the films that are sealed up 

 by the subsequent coatings. The process is apparently 

 rather tedious, as there are three collodion films, six 

 gelatine coatings, and a final coating of varnish to dry. 

 The obvious objection to the number of films because 

 of their combined thickness is probably invalid, as the 

 collodion and the gelatine solution used are weak and 

 the films they give correspondingly thin. ,\ real diffi- 

 culty I should have expected to be due to the action of 

 the chloracetic acid on the gelatine films under the 

 collodion film that is being subjected to the fixing 



