February i, 1906] 



NA TURE 



Messrs. Lumiere gets over this difficulty of the lines by I 

 coating a plate with a single layer of starch granules | 

 which have been previously suitably coloured in three | 

 batches and then well mixed. The disposition of the three 

 required colours is thus irregular, and the separate points 

 of colour are too small to be discriminated by the naked 

 eye. I nfortunately, no example of this method is on view ; 

 probably the inventors do not care to show their results 

 until they have perfected the process. But this is the only 

 notable process not represented. 



In the rest of the exhibits the three coloured prints are 

 superimposed, the variations being in the methods of their 

 production and assembling. In the Sanger-Shepherd 

 process three separate films are prepared, stained, and 

 cemented together. Several exhibitors have adopted this 

 process, chiefly in the production of transparencies, but 

 there are a few prints on paper, and of these a portrait, 

 Xo. 11, is worthy of special commendation. Dr. B. 

 Jumeaux's modification consists in getting the blue element 

 as a toned bromide print, and then superimposing the red 

 and yellow films. Captain Lascelles Davidson and Mr. O. 

 Pfenninger show specimens in which the films are super- 

 imposed but not cemented together, and there are other 

 modifications that are not described. 



instead of three stained films, the prints may be pre- 

 pared from pigmented tissue by the ordinary carbon 



pr ss. The Autotype Company, the Rotary Photographic 



Company, Mr. \Y. E. Brewerton, M. Leon Vidal, the 

 Lumiere X.A. Company, and Dr. A. Hesekiel and Co. 

 exhibit prints by various modifications of this method of 

 working, the last named adopting the Selle process in- 

 [roduced several years ago. Mr. W. E. Brewerton shows 

 how the gum bichromate process may be adapted for the 

 purpose, each of the three coloured elements being pro- 

 duced in turn on the same sheet, with no transferring. 

 The two " winter landscapes " by Dr. H. Bachmann are 

 stated to be three-colour prints in gum bichromate, but 

 the colours are scarcely, if at all, perceptible. The " pina- 

 ivpe " process has recently been described in these columns. 

 In this case three colours are absorbed in turn into a 

 single gelatin film from prepared gelatin films previously 

 si aked in the colour solutions. Messrs. Fuerst Bros, show 

 specimens of it, and Dr. E. F. Grim some results of un- 

 <l<—cribed modifications. 



One of the most interesting exhibits is the group 

 numbered from S 2 t0 5°. examples of coloured prints 

 obtained by a single exposure of a piece of coated paper 

 under the coloured original, the colours being reproduced 

 in the print. The sensitive material has the necessary- 

 three colours, each in its own film, superimposed, so that 

 it appears black. By exposure to white light the dyes are 

 all bleached, but if the light is coloured the corresponding 

 colour is not bleached, because the dye does not absorb 

 light of its own colour. This process has been worked at 

 for many years by several investigators, the fundamental 

 difficulties being to find the colours of the right tints that 

 shall be sufficiently sensitive, that is fugitive to light, and 

 can be made sufficiently stable when the print has been 

 produced. These examples are by Szczepanik's method, 

 and show surprisingly bright and clean colours. It is a 

 pity that the original " lithophanes " are not shown as 

 well as the copies, as many will doubtless consider that 

 thev are withheld because the comparison would not be to 

 the advantage of the prints. Whether this is so or not, 

 the results are wonderfully good considering the difficulty 

 inherent in such work. 



Of the three negatives exhibited by Dr. J. H. Smith and 

 Co., obtained by one exposure in an ordinary camera, the 

 plate used having superimposed on it three sensitive films 

 with the necessary colour screens, there is nothing to be 

 said, as there is no example of the plate used or of the 

 print that the negatives might give. The results on 

 " multico " tissue, which has several layers of pigmented 

 tissue and is used as in carbon printing, the " mars star " 

 prints which are produced by applying colours to bleached 

 bromide prints, and the two portraits by Mr. Burgess can 

 hardly be regarded as serious attempts to reproduce mech- 

 anically the colours of the originals until more is known 

 about them. They are better described as colour effects, 

 ;nnd there might be some interest attaching to them if the 

 methods of their production were known. C. J. 



no. 1892, voi. 7$] 



T 



THE INTERNATIONAL METEOROLOGICAL 



CONFERENCE AT INNSBRUCK. 



Fourth Meeting, September 14, 1905. l 



HE president, Prof. J. M. Pernter, announced that 

 after the discussion of a proposition made by Father 

 Froc the meeting would proceed to elect the International 

 Committee. By accepting Father Froc's proposition, the 

 committee recommended the observation of the zodiacal 

 light whenever possible, and assigned a definite symbol 

 for use in reports. 



On the proposition of Prof, von Bezold, the following 

 committee was re-elected : — Messrs. Chaves, Davis, Eliot, 

 llellmann, Hepites, Iiildebrandsson, Lancaster, Mascan, 

 Mohn, Moore, Palazzo, Paulsen, Pernter, Russell, 

 Rvkatcheff, and Shaw. 



Also, on the proposition of Prof, von Bezold, Prof. 

 Nakamura, of Japan, was elected in succession to the late 

 Dr. Billwiller. 



Prof. Pernter proposed that the presidents of the com- 

 missions should be added to the committee, but it was 

 decided that six months' notice should be given of any 

 propositions which would affect the constitution of the 

 committee. 



Prof. Hildebrandsson presented the report of the com- 

 mission on squalls. It was arranged that the question of 

 the studv of squalls should be left in the hands of Messrs. 

 Durand-Greville, Hildebrandsson, and Shaw, and that 

 meteorological institutions, including aeronautical stations, 

 should be asked to send to these gentlemen, upon demand, 

 for a certain number of days, about ten per year, the 

 necessarv observations for the construction of accurate 

 charts of isobars, with the diagrams of pressure, tempera- 

 ture, and wind for the purposes of this special study. 



Prof. Hellmann reported on behalf of the commission on 

 the international code and on the comparison of baro- 

 meters. The conference considered the publication of 

 tin- international code, of the resolutions passed by, and 

 of the papers presented to, the international conferences to 

 be a valuable and powerful means of facilitating and 

 developing international meteorological research, and ex- 

 pressed a hope that the meteorological institutions in 

 Berlin, Paris, and London would undertake the publication 

 in German, French, and English. Thanks were voted to 

 Father Algue, who proposed to publish them in Spanish, 

 and to Profs. Hellman and Hildebrandsson for their pre- 

 paration of the code. 



After some discussion as to the best means of comparing 

 the barometers in different countries, it was decided to put 

 into operation the decision of the conference at Vienna 

 relating to the inspection of the stations in the control of 

 each country- The comparison, wherever possible, was to 

 be extended to extra-European countries. This work was 

 left to Prof. Hellmann and General Rvkatcheff. 



General Rvkatcheff presented propositions from the 

 magnetic commission dealing with the necessity of bring- 

 ing the magnetic instruments in the various observatories 

 into agreement, and with the desirability of an early 

 exchange of diagrams after days of magnetic storms, ot 

 whenever the records may be specially interesting. 



Fiftli Meeting, September 15, 1905. 



The president of the solar commission, Sir Norman 

 Lockyer, presented the report of the meetings of that com- 

 mission during the preceding days, and also the report of 

 the meeting at Cambridge in 1904. The committee 

 approved of all the resolutions contained in the report, and 

 re-elected the commission, with Sir Norman Lockyer again 

 as president. 



The commission expressed the opinion that permanent 

 meteorological observatories should be established in the 

 north of Siberia and America, at least two or three in 

 each country, it also desired to obtain all the observations 

 that may have been made in a large number of islands 

 scattered over the globe, the names of which were given, 

 and insisted on the necessity of continuing these observ- 

 ations, asking that the attention of the Governments con- 

 cerned should be directed to this matter. Directors of 



1 Reports of the proceedines of the first three meetings appeared in 

 Nature of September 21 and October 5, 1905 (vol. lxxii., pp. 510 and 562). 



