34 



NA TURE 



[May 12, 1892 



or third examination candidates who have been rejected 

 on their first trial. This is a proof of one of two things : 

 (i) either that the tests employed were bad, or else 

 that colour-blindness had been cured or mitigated. There 

 is no evidence to show that congenital colour-blindness is 

 curable ; in fact, what there is is in exactly the contrary direc- 

 tion. For although it is true that reds and greens may be 

 correctly named by a colour-blind person, by making him 

 notice certain slight difference in the intensity or purity 

 of the one colour which represents both of these to him, 

 yet no amount of education or coaching would enable him 

 to distinguish between them under the varying atmo- 

 spheric conditions under which the signals are seen. The 

 Committee bad practical trials of various tests made before 

 them at Swindon and elsewhere, with the result that the 

 Board of Trade tests for the mercantile marine allowed 

 several individuals to be passed as possessing normal 

 colour vision whom other tests distinctly proved to be 

 markedly and probably dangerously colour-blind. Under 

 these circumstances it is not surprising that they have 

 condemned such a system of testing, more especially as 

 it is one which necessitates the naming of colours, and 

 recommend those of Holmgren, which have long given 

 practical proof of their ability to discriminate between 

 normal and even slightly defective colour-perception. 



The Holmgren test consists in requiring a candidate 

 to select from a large assortment of wools those colours 

 which appear to him to match a skein of pale yellowish 

 green, a pale pink, and a bright crimson. These pale 

 colours are sure to be matched by the colour-blind 

 with colours which are totally different in hue, and the 

 nature of the mistakes made infallibly indicate the 

 character and danger of the blindness. 



The evidence shows that some railways have been 

 under the impression that they were using the Holmgren 

 test, but when the colours were examined critically it was 

 found that the hues of the test-skeins of wool were per- 

 fectly different from those determined by the distinguished 

 Swedish investigator. If the two trial test-colours of 

 Holmgren were more brilliant and of rather different hues, 

 it is quite possible that persons with defective colour 

 sense might make correct matches, and pass an examina- 

 tion which they really never should do. It is for this 

 reason that the Committee recommend that the standard 

 test-colours should be officially passed by an expert 

 attached to the Board of Trade, as also those colours 

 with which the colour-blind would most probably match 

 them. 



. There are several of the recommendations which are 

 especially valuable ; for instance, that one by which the 

 test should only be intrusted to examiners certified as com- 

 petent to conduct the examinations. It is obvious that to 

 have an efficient examination, not only should the test be 

 efficient, but also the examiner. We have heard of a rail- 

 way foreman being armed with a variegated bunch of 

 wools, and insisting on candidates for employment naming 

 them, and rejecting those who failed to give the name 

 which he considered should be given. Such a test by 

 such an examiner is evidently useless and cruel. The 

 right of appeal by the rejected candidates is also whole- 

 some, though it will probably be very rarely exercised ; 

 and as the tribunal to whom such an appeal can be 

 carried is an expert, we may be certain that substantial 

 justice will be meted out. 



The whole report is valuable, but the labour will be 

 thrown away unless legislative measures are taken to 

 render it effective. It is no use telling railways what they 

 ought to do, but only what they must do, in such examina- 

 tions as are in question. The subject of colour vision is 

 one which is so open to fads that the public require 

 to be safeguarded from faddists who might happen to 

 have ear of Boards of Directors or general managers ; 

 for this reason we hope that reasonable legislative action 

 may be taken within a reasonable time. 



NO. I 176. VOL. 46I 



THE GREAT EARTHQUAKE IN JAPAN, 1891.' 



"lyW'HILE the occurrence of a great earthquake in a 

 ** district intersected by railways, and traversed by 

 telegraph wires, brings forcibly before the mind — even of 

 the most casual reader of newspaper reports— the awful 

 and destructive results of such a catastrophe, the scientific 

 man cannot fail to note that it is under such conditions 

 as these the best opportunities will be found for obtaining 

 the necessary data upon which to reason concerning 

 these terrible and still little understood movements of 

 the earth's crust. In connection with the Seismological 

 Society of Japan, a system of reporting the times and 

 chief features of earthquake-shocks has been for some 

 years in successful operation, and all station-masters 

 and Post Office agents are required to transmit their 

 records to a central office ; the electrical control of the 

 clocks of course giving these reports a value which they 

 would not otherwise possess. 



Two considerable earthquakes in recent years have 

 occurred in areas where it was possible to obtain a great 

 mass of accurate time and other observations, and 

 these can scarcely fail to be of great value to the seismo- 

 logist. The terrible earthquake of Charleston, oh August 

 31, 1886, was felt overagreat part of the United States ; 

 and at the railway stations, post offices, and other places 

 where the accurate time was kept, many valuable obser- 

 vations \yere made. The vast mass of material collected 

 has been dealt with by Prof. Simon Newcomb and 

 Captain C. E. Button; and from the Report published by 

 the United States Geological Survey, some remarkable 

 and striking conclusions regarding therate of movement of 

 earthquake waves would appear to have been established. 

 The Gifu or Ai-Gi earthquake of October 1891 has 

 yielded data which the able seismologists of Japan may 

 be trusted to make the fullest use of, when sufficient time 

 has elapsed for the comparison and discussion of the 

 reports. 



As a preliminary notice and striking memorial of the 

 catastrophe, the beautiful volume now before us will be 

 gladly welcomed. The book consists of twenty-nine 

 permanent photographic plates, printed on excellent 

 paper, and forty-six pages of letterpress. The energetic 

 authors of the book were on the scene of the earthquake 

 immediately after its occurrence, and all the plates, 

 except three, are reproductions of photographs taken 

 by Prof. Burton for the Imperial University. It is 

 difficult to realize that the collection of the materials for 

 this handsome book, with the execution of its luxurious 

 typography, illustrations, and binding have been all com- 

 pleted within the short space of two months, and it says 

 much for the enterprise and activity of the Japanese 

 publishers, as well as of the authors, that such a result 

 should have been possible. 



One of the most striking effects of the Charleston 

 earthquake, as described in Captain Button's report, was 

 the twisting laterally of the permanent way on railway 

 lines. On Plate x. of the work before us a similar 

 serpentine twisting of the railway, suggesting a perma- 

 nent compression in the line of the rails, is shown to 

 have been effected, and the photograph constitutes a 

 beautiful permanent record of the result. Still more 

 striking are the phenomena displayed at some of the 

 railway bridges, especially that of Nagara Gawa, which 

 is very fully illustrated in Plates xxii., xxiu,, xxiv., 

 XXV., and xxvi. Our illustration is a reproduction of 

 one of these plates. Not only have the lattice-work sec- 

 tions of the bridge been snapped asunder, but the great 

 tubular piers have been thrust through the floor on which 

 the railway lines are laid, these latter being forced up in 



' "The Great Earthquake in Japan." By John Milne, F.R.S.. Professor 

 of Mining and Geology, and W. K. Burton, C.E., Professor of Sanitary En- 

 gineering, Imperial University of Japan. With Plates by K. Ogawa. 

 (Yokohama, Japan : Crawford and Co. London : E. Stanford, 1892.) 



