114 



NA TURE 



[January 14, 1909 



results true hcemog-lobinamia followed by hemo- 

 globinuria." Parasitic, osmotic, and chemical actions 

 having^ been excluded as causes, it seems to the 

 authors " most probable that black-water fever is due 

 to some specific ha>molysin arising' within the body " 

 as the result of certain conditions, induced by repeated 

 attacks or infections by malaria. The hEemolysin is 

 believed not to be derived from the malarial parasites 

 themselves, but to be thrown out by the cells of the 

 body in response to stimulation, as a result of the 

 constant phagocytosis of red cells. " If hsemolysins 

 are formed against the blood there seems no agent 

 so likely to effect this as the endothelium." The 

 prophylaxis of black-water fever is " simply the pre- 

 vention, as far as possible, of malarial infection, and 

 the prompt and efficient treatment of this disease." 

 In the palliative treatment of black-water fever the 

 authors wish to show that " there are excellent 

 reasons for believing that good results may be 

 expected from scrum-therapy." 



The Government of India is greatly to be congratu- 

 lated on the onlighlcned manner in which it aids 

 forward the production, and undertakes the publica- 

 tion, of important and valuable investigations of this 

 kind. 



A^niAlED PHOTOGRAPHS IN NATURAL 

 COLOURS. 

 ""PHE production of ];hotographs in colour by means 

 ■*• that may fairly be described as photographic is 

 now quite common. Though the simple method of 

 getting pigmentary colours in the picture bv the direct 

 impact of the coloured lights proceeding from the 

 object has not been, and may never be, realised, e.K- 

 cept, perhaps, to a certain extent by very prolonged 

 exposures, the indirect three-colour process in its 

 numerous modifications has thoroughly established 

 itself as a quite practical method. It is natural, 

 therefore, that endeavours to get kinematograph views 

 shown on the sheet in natural colours should follow 

 on the same lines that have made such great successes 

 possible in single photographs. 



Three-colour projection involves the taking of three 

 negatives and the making from these of three suitably 

 coloured positive transparencies which niav then be 

 superposed to form a single coloured transparency, or, 

 using suitable colours, projected by three lanterns 

 separately upon the screen and superposed there. The 

 latter method would obviouslv commend itself in 

 kinematography, because of the difficulty, if not the 

 impossibility, of uniting three long strips into one, 

 maintaining correct superposition from one end to the 

 other. Besides, three lanterns would obviouslv give a 

 good illumination on the screen more readily than one 

 lantern. Many attempts, or at least suggestions, for 

 it is difficult to know whether a verbal description 

 really means anything more, have been made in this 

 direction. Mr. G. Albert Smith, in a lecture recently 

 given at the Royal Society of Arts, described the 

 difficulties he met with in a really practical and per- 

 severing attempt, in conjunction with Mr. Charles 

 Urban, to succeed on these lines. There was not 

 only the difficulty of photographing with the neces- 

 sarily short exposure through the red screen, which 

 was eventually overcome, but the practical impossi- 

 bility of getting correct, or even passablv correct, 

 registration of the three pictures on the screen. This 

 is a very different problem in kinematographv from 

 the production of a single three-colour picture. Ob- 

 viously the three series of photographs must be taken 

 simultaneously, and although the three kinematograph 

 cameras may be synchronised, as they are necessarily 

 somewhat bulky, the three points of view must be 

 separated, and this introduces differences in the pic- 



NO. 2046, VOL. 7y] 



tares analogous to the differences between the indi- 

 viduals of a stereoscopic pair. But this is not the 

 only difficulty. It is comparativelv easy to get three 

 pictures on the screen from three lanterns or a triple 

 lantern correctly superposed when the lanterns are 

 quite still; but it is a very different matter in the 

 case of kinematograph projection apparatus, for here 

 the film runs through it in a series of rapid jerks, and 

 the slightest movement of the apparatus produces a 

 very much increased effect on the screen, because of 

 *he very considerable magnification necessarv. Mr. 

 Mbert Smith describes the result of his best attempts 

 ts " unbearable confusion." 



All the mechanical difficulties of registration, and 

 the dissimilarity of the photographs taken from three 

 points of view, are done away with by using one film 

 only and allowing the three coloured images to 

 alternate. This has, further, the very great advan- 

 tage of simplification, for the apparatus for talking 

 and projecting is single only instead of three-fold. Ot 

 course, the fihn must pass more quickly through the 

 apparatus, as it requires three pictures to form the 

 single complete impression instead of one. The 

 difficulties of this are obvious in a general sense, and 

 it also means a shortening of the exposure time in 

 taking the pictures, a disadvantage especially with 

 the red and green screens. Still, the method was 

 successful, but Mr. .Mbert Smith found the colours 

 to be " washy and ineffective." It is not obvious 

 why this must needs be so ; probably the defect might 

 have been remedied, but Mr. Smith applied himself 

 to further simplification, and aimed, in spite of 

 theory, at reducing the colour records to two. In this 

 he has been surprisingly successful, as his demon- 

 strations show. It is not easy to follow his reasoning 

 as to the most suitable colours, but as a matter of 

 fact it seems that he uses a red inclining to orange 

 and a green inclining to blue. The two colour screens 

 are on a disc that rotates in front of the lens so that 

 each alternate picture is taken and afterwards pro- 

 jected through the one colour. Thus the ordinary 

 apparatus is available by the addition of the rotating 

 disc that carries the colour screens, there is no 

 difficulty with regard to registration, and the increase 

 in speed of working', as compared with the ordinary 

 kinematography, is doubled only instead of tripled. 

 Doubtless there are imperfections in the colours, but 

 the same may be said of all three-colour work. It 

 has, however, been demonstrated that greys are fairly 

 well reproduced, and that there are no striking errors 

 even in such compound colours as purples. A com- 

 parison of the results soobtained with an autochronic 

 slide made of the same view shows practically no 

 difference to the ordinary observer. We may there- 

 fore say that Mr. Albert Smith's method is not only 

 very good as a first step towards kineniatography in 

 colours, but that it is a really practical methed. 



PROF. H. G. SEELEV, F.R.S. 



THE death of Prof. H. G. Seeley, which took 

 ])lace at his residence on the morning of January 

 8, makes a big gap in the ranks of the compara- 

 tively small body of British vertebrate palaeontologists, 

 among whom the deceased professor was entitled to 

 rank as the doycii. Born in London in February, 

 1839, he seems to have acquired literary and scientific 

 tastes at an early age, and in the 'sixties we find 

 him established at Cambridge, where he was taken 

 up by the late Prof. .Adam Sedgwick, and employed to 

 work at the fossil vertebrates then being rapidly accu- 

 mulated in the Woodwardian Museum, and likewise 

 to lecture on geology when the aged professor was 

 incapacitated from doing so by infirmity or illness. It 

 was at this tinie that the so-called coprolile diggings 



