January 27, 1910J 



NA TURE 



371 



only to be interpreted accurately in the light of a com- 

 prehensive knowledge of the physiology of vision. 



We have the profoundest respect for the work which 

 Sir William Abney has done upon the subject, and 

 every competent critic will endorse the opinion of 

 Lord Rayleigh, quoted by Lord Hamilton of Dalzell, 

 that the Board of Trade could not be wrong in follow- 

 ing his advice. How is it to be explained, then, that 

 his opinion, endorsed by other competent men of 

 science, is not accepted as final? We think that it is 

 largely due to the difficulty, or rather impossibility, 

 of conveying to laymen any adequate conception of 

 the peculiarities of vision of the colour-blind. The 

 diflicultv is enhanced by the terminology and phrase- 

 ology adopted by the expert, who almost invariably 

 speaks, as it were, in the language of the theory of 

 colour-vision which he personally affects. Thus, Sir 

 William Abney describes a man in terms of the 

 ■^'oung-Helmholtz theory as red-blind, whilst Dr. 

 f^ivers, agreeing entirely with the facts of the colour- 

 vision of the individual, describes him as red-green- 

 blind, and would doubtless prefer to avoid all 

 ambiguity by calling him scoterythrous. Every state- 

 ment which either might make in endeavouring to 

 convey some idea of the visual perceptions of a 

 colour-blind individual to one who has had no train- 

 ing in the physiology of the senses might be implicitly 

 relied on tor accuracy when rightly interpreted, but 

 ihe probabilities of correct interpretation are exceed- 

 ingly small, if, indeed, the whole statement is not 

 regarded as a meaningless jargon. 



Further, the layman fails wholly to understand why 

 recondite tests, such, for example, as that with simul- 

 taneous contrast colours, should be imposed upon the 

 examinee. He can comprehend "practical" tests on 

 board ship, such as that to which Mr. Trattles sub- 

 mitted. It would surprise him greatly to be told that 

 under favourable atmospheric conditions the expert 

 woula fully expect a colour-blind person to pick up 

 lights with unfailing accuracy. 



The Trattles case vv-ill have served an invaluable 

 purpose if, as must inevitably be, it focusses public 

 cpinion upon the glaring anomalies of the examina- 

 tion in colour-vision of candidates by the Board of 

 Trade. It appears to us to be imperative that all the 

 conditions should be re-investigated by a competent 

 body, either a carefully selected Royal Commission or 

 a committee of the Royal Society upon which physio- 

 logists and ophthalmologists who have devoted special 

 attention to the subject are adequately represented. 

 Among the duties of such a committee would be : — 



(i) Re-investigation of the tests for colour-blindness 

 with the view of the adoption of methods less open to 

 attack, and, if possible, of a simpler nature. 



(2) Re-organisation of the examinations and of the 

 boards of examiners. 



We have no doubt that it would be possible so to 

 revise the conditions of the Board of Trade examina- 

 tions that it would cease to be necessary to have 

 recourse to a court of law for adjudication on the 

 results of a purely scientific question. 



NATURE PHOTOGRAPHY.' 

 'T^HE object of Mr. Bedford's book is to encourage 

 •^ the pursuit of nature photography among those 

 who cannot afford either the time or expense to under- 

 take very advanced work in this direction. The author 

 rightly points out that there are great advantages in 

 this method of studying nature over the older method 

 of collecting, and that the study of natural history 

 by means of photography may be taken up by those 



1 "Nature Pholography for Beginners." By E. J. Bedford. Pp. .\iv + 

 168. (Lond)n : J. M. Dent and Sons, Ltd., 1909.) Price js. td. net. 



NO. 2100, VOL. 82] 



whose time and means are strictly limited. The first 

 part of the book deals with the apparatus required. A 

 detailed description is left to text-books on photo- 

 graphy ; some knowledge of cameras and photographic 

 methods is assumed, and the author confines himself 

 to suggestions and to an account of the particular 

 kinds of apparatus which he himself has found service- 

 able. On the whole, this part of the book should be 

 valuable to a beginner taking up the subject for the 

 first time, but one feels that in some parts space is 

 wasted in describing processes of which a sufficient 

 account is given in every book on photography, and 

 other parts might with advantage be made more full, 

 for in places the reader is left with no clear idea of the 

 nature of the instrument or process recommended. 

 Rough estimates of cost might also have been in- 

 cluded ; several times we are told that the choice must 

 be decided by the possible outlay, but no actual 

 estimates of expense are given. 



The second part of the book deals with the actual 

 photography of living objects. In the chapter on 

 choice of subjects, the author very rightly empha- 



Red .Admiral Butterfly (wings expanded). From " Nature 

 Photography for Beginners.'' 



sises the fact that a connected series of photographs 

 of one subject or group of subjects is of much greater 

 interest and value than an indiscriminate collection 

 of pictures of isolated things. This is illustrated in 

 the book by the series of plates (Figs. 69-76) showing 

 the early life of a young cuckoo. We regret that the 

 chapter was not extended somewhat, at least so far 

 as to emphasise the value of photographic records of 

 objects which cannot easily be collected or preserved in 

 their natural condition, such as fungi, insect larvae, or 

 fruits. As an illustration of the excellent results that 

 may follow from the patient collection of photographs 

 of such things, one may mention Connold's useful book 

 on " British Oak Galls." 



The chapters on how to observe and photograph 

 the commoner birds and their nests take the form 

 of a conversation, or rather discourse, to an imaginary 

 novice during a series of birds'-nesting excursions. 

 This style of writing is very irritating, as are the 

 frequent references to the pleasures of tea in the 

 country, and these chapters might lead one who had 



