222 



NATURE 



[July 6, 1893 



LETTERS TO THE EDITOR. 



[ The Elitor does not hold himself responsible for opinions ex- 

 pressed by his correspondents . Neither can he undertake 

 to return, or to correspond with the writers of, refected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications . ] 

 Identification. 



Permit me to make in your columns a few remarks on the 

 following topic : — 



It is now well known that the Council of the British Association 

 have lately memorialised the Secretaries of State for the Home 

 Department, Army, Navy, India, and the Colonies, expressing 

 an opinion that the Anthropometric methods for Identification in 

 use in France and elsewhere, deserve serious inquiry, as to their 

 efficiency, the cost of their maintenance, their general utility, 

 and the propriety of introducing them, or any modification of 

 them, into the Criminal Department of the Home Office, into 

 the Recruiting Departments of the Army and Navy, or in the 

 Indian and Colonial Administration. 



In connection with this suggested inquiry I have some very 

 recent information to give as regards the inclusion of finger prints 

 among the records that a Imit of being usefully employed in bertil- 

 lonage. This convenient term has been coined to express the prin- 

 ciple of the French system, invented and directed by Alphonse 

 Bertillon, of s :■ classif) ing anthropometric records that each can be 

 sorted into its own natural group, just as each surname falls into 

 its alphabetical place in a common directory. There may be 

 many Smiths, but every Smith will be found among the 

 Smiths and not among the Browns. There may be doubt about 

 the exact spelling, and the Smythes will have al.-o to be 

 searched, but the range of uncertainty as to where 

 to look for the required name will always be narrowly 

 limited. So it is with the ordinary anthropometric records ; 

 so also it is with finger prints, which are as yet unused 

 in the French system. Those who have read my book on the 

 subject will recollect that the index letters for finger prints are 

 limited to a, u, r, or w, as the case may be, for the two fore- 

 fingers, and a, I, w, for the remaining eight digits. These produce 

 such combinations often letters as ral, ull ; wl, II, which are ar- 

 ranged alphabetically. The test of the efficiency of this system 

 lies, first in the sureness with which different (instructed) per- 

 sons assign the same index letters to the same indifferently 

 printed set, and secondly in the degree to which the sets are 

 diffjrentiated by their classification. Now I possess and have 

 examined some thousands of well printed sets of students and 

 others at my laboratory ; but. until very recently I had no large 

 collection of (//-printed sets ai prisoners. This want has been 

 at length supplied in the following manner, by which I am 

 alile to confirm previous conclusions. Lieut. -Col. Surgeon 

 Hendley, whose energetic furtherance of science and art at 

 Jeypore is well known, was in charge last year of the 

 Maharajah's magnificent contribution to the Imperial Institute, 

 and, having visited my laboratory, became much interested in 

 finger prints, arid promised to send me a collection taken 

 from the gaols of Jeypore. It arrived not very many days 

 ago, too late to be alluded to in my recently issued supple- 

 mentary chapter on the Decipherment of Blurred Finger(Prints. 

 It contains nearly a thousand cards, each card bearing the 

 impressions of all the ten digits of a different person. They 

 were printed by pressing the finger first on the pad used for 

 inking the office stamp and then on the card. This method, 

 as I have recently had occasion to point out, gives far inferior 

 results to that of printers' ink. So far as the Jeypore col- 

 lection shows favourable results, a similar collection printed 

 in the way always used in my laboratory would give still 

 better ones. 



Consequently, the Jeypore collection is particularly serviceable 

 for arriving at moderate conclusions ; moreover, their number 

 is sufficiently large to justify them. My assistant marked the 

 appropriate index letters on each card, and I compared them with 

 my own independent determinations. The result was very favour- 

 able ; our readings practically agreed, and although most of the 

 prints were faint, orblurred,orotherwi3e imperfect, it was possible 

 to classify nearly all of them. This affords a strong confirmation 

 to my formerly expressed belief that the method of finger prints 

 must, in time, come into use as an important and supplementary 

 aid to bertillonagc. The process of taking the impressions is ex- 

 tremely simple after it has been learnt and the small but neces- 

 sary equipment is at hand. At the same time, there is no 



NO. 1236, VOL. 48] 



undressing necessary, and nothing else of a humiliating characi 

 to be undergone during the brief act of making the prints. 



I shall not here enter upon the unique and exiraordins 

 power of finger prints in enabling us to determine, irrespectivi 

 of age and growth, whether two clear impressions, taken at d 

 ferent dale?, were or were not made by the same finger, 

 does not depend on that general pattern of the print which 

 the basis of classification, but upon the numerous forks a 

 other details in the ridges that compose the patterns. Tl 

 has been fully dicussed and proved in my two books, and I ha 

 nothing new to saj', except that in my laboratory 1 have nf 

 upwards of 300 complete duplicate sets to work upon, the \.\ 

 members of each of which were taken at times separat 

 by various intervals rarging between one and three yea 

 These intervals are too short to be of much value, but the ci 

 lection will increase in importance as the years go by, ai 

 further repetitions of prints from the same fingers shall ha 

 been made. 



My letter is already long, so perhaps you will permit me 1 

 another occasion to recur to the action of the Council of tl 

 British Association, and to indicate thecharacter of the inform 

 tion regarding the etliciency, cost, and utility of berlillona 

 that might be gained with little trouble officially, but which 

 almost beyond the reach of any private person to obtain. 



Fran'Cis Galton. 



The Publication of Physical Papers. 



Mr. Swinburnk in his letter on this subject has omitti 

 to recognise the existence of a society which is older and qui 

 as important as the Physical Society, I mean the " Londi 

 Mathematical Society." 



For reasons which it is unnecessary to enter into, I fear th 

 an impression has unfortunately got abroad that the Londt 

 Mathematical Society is an institution which exists solely f 

 the advancement of pure mathematics. No greater error ecu 

 be made ; for whatever may have been the case in the earli 

 days of the society, the council for some years past have bee 

 fully alive to the importance of doing everything they can I 

 encourage mathematical physics, and to induce physicist 

 whether members of the society or not, to communicate pape 

 on mathematical physics. In short, the policy of the count 

 at the present time is to endeavour to hold the balance even 

 between the two branches of mathematics, and not to favoi 

 the one more than the other. 



The policy of the society is still further exemplified by tl 

 fact that on the last two occasions the De Morgan medal hi 

 been awarded alternately to a mathematical physicist and to 

 pure mathematician ; and during the discussion w lich too 

 place in connection with the last award to Prof. Klein, seven 

 members of the council expressed a hope that this practic 

 would be followed in future years. 



A scientific newspaper like Nature is scarcely suitable forth 

 publication in extenso of papers relating to mathemalic 

 physics ; but it may be well to point out that the Londo 

 Mathematical Society presents contributors of papers wit 

 twenty-five gratuitous copies, whereas the proprietors of ih 

 Philosophical Magazine refuse to present gratuitous copies or t 

 remunerate contributors in any way whatever. Moreover, ih 

 Proceedings of the Society can be purchased by the publi< 

 whilst (according to Mr. Swinburne) those of the Physic; 

 Society cannot. Also abstracts of papers read at the meeting 

 of the London Mathematical Society can always, if the authc 

 wishes it, be published in Nature, and can thus be at one 

 brought before the notice of the scientific public. 



It will thus be seen that the London Mathematical Societ 

 offers greater advantages to contributors than the Physica 

 Society or the Philosophical Magazine ; and when this fact i 

 once recognised I venture to hope that physicists will not stani 

 aloof from the Society in the way that many of them ha* 

 hitherto done. A. B. Basset. 



A Simple Rule for finding the Day of the Week corre 

 spending to any given Day of the Month and Year. 



Mr. H. W. W., in Nature, vol. xlvii. p. 509, gives 1 

 simple rule for finding the day of the week corresponding I' 

 any given date. It seems that this rule could be made stil 

 more simple. Thus, let 



A = number of the given year. 



B = number of the day in the year. 



C = number of leap years from A.D. i to the teginning 



