90 



KNOWLEDGE. 



[April 1, 1901. 



are very considerable difficulties attacliing to M. Faye's 

 foi-m of the theory. I give it only as an example of 

 one way in which it has been attempted to explain the 

 fact to which Mr. Christopher alludes. — E. Walter 

 Maunder.] 



IS HUMAN LIFE POSSIBLE ON OTHER 

 PLACETS? 



TO THE EDITORS OF KNOWLEDGE. 



Sirs, — ^Referring to Mr. Thomas R. Waring's reply 

 to Mr. A. D. Taylor's qiiery, " Is human life possible on 

 other planets? " he states that Mars' atmosphere is thin, 

 and consequently free from clouds. In Wells & Gregory's 

 Honours Physiography, as well as in various other bocks, 

 it is stated that Mars possesses clouds which are visible 

 in the large telescopes as dark moving patches. I should 

 like to know which of the above is right. If Mars pos- 

 sesses no clouds on account of its thin atmosphere, I 

 should like to know what atmosphere has to do with 

 clouds. E. Lloyd Jones. 



Blaenau Festiniog. 



[I do not remember the passage in Wells and Gregory's 

 Physiography, but it should be-j)oiuted out that clouds 

 on a planet in opposition would necessarily appear as 

 extremely bright bodies, not dark ; whilst it is in the 

 last degree improbable that any cloud motions could be 

 perceived. A white spot uj^on Mars might conceivably 

 be due to snow, hoarfrost, or cloud, and it would be 

 quite impossible for us to discriminate at our immense 

 distance from the planet between the three. On our 

 earth dense and widely extended clouds are confined 

 to the lower regions of the atmosphere. The upper 

 strata, which approximate in tenuity to what we can 

 conceive of the atmosphere of Mars, support nothing 

 but thin cirrus clouds, which could not possibly be dis- 

 cerned as such across 40 millions of miles. — E. Walter 

 Maunder.] 



HUMAN FINGER-PRINTS. 



TO THE EDITORS OF KNOWLEDGE. 



Sirs, — The constancy of human finger-prints has 

 chiefly been discussed in connection with the identifi- 

 cation of criminals. Assuming that the evidence of 

 finger-prints is to be admissible in criminal proceedings, 

 it will be not only necessary to prove that in the case of 

 the same man the finger-prints remain unaltered, but 

 that no two persons have identical finger-prints. Wliere 

 is the evidence of this? There are probably 1,500,000,000 

 of men and women on the earth. Can we suppose that 

 no two of these have identical finger- jjrints ? Nor in- 

 deed is this all. We may be comijaring the finger-prints 

 of a living man with those of one who has been dead 

 for years past, and the doctrine of heredity might lead 

 us to expect to find similar fingei'-jjriuts in the case of 

 parents and children, and of different childi'en of the 

 same parents. It is, at all events, certain that if this 

 finger-print system were once introduced into our courts 

 of justice, there would be any amount of wrangling as 

 to whether they were identical or only similar — experts 

 contradicting each other and involving the whole subject 

 in confusion. Moreover, professional criminals would 

 probably soon find some mode of altering their finger- 

 prints. No doubt if the person who committed a crime 

 — a murder, for example — has left the imprint of his 

 fingers on anything it may prove an important clue ; 

 but the same thing may be said of the imprint of his 



boots or shoes. But a clue is one thing and a proof 

 is another thing. 



Let me point out another difiiculty. In a country 

 where there are a lai'ge number of criminals whose finger- 

 prints are collected, the number of these will soon be 

 very large. How long would it take to examine this 

 collection in order to find out whether any of them 

 corresponded accurately with the finger-prints of the 

 man who is now accused? The task would, I think, 

 be a hopeless one. 



That finger-prints may be important in the detection 

 of crime whenever the criminal has left the print of his 

 fingers behind him I do not dispute, but without much 

 stronger evidence than we now jDossess that no two 

 persons have undistinguishable finger-prints such 

 evidence ought never to be permitted to outweigh what 

 apjjeared to be a tolerably satisfactory alibi. As to 

 persons guilty of repeated crimes, I do not see the justice 

 of adding to a man's sentence on the present occasion 

 because he has fully expiated a previous offence ; while 

 a really habitual criminal can never pose as a first 

 offender under our present system, although some of his 

 pi-evious convictions may be overlooked. 



W. H. S. MoNCK. 



MiTfSfi 



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ORN1THOLOG1CAD> 



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NOTES:-. 



Conducted by Harry F. Witeerbt, f.z.b., m.b.o.u. 



Early Appearance oi? the Dotterel in Yorkshire. 

 — Two Dotterels {Eudromias vwrineJlns) were seen here 

 on February 18th, and one a»ain on March 2nd. These 

 are surely extraordinary early dates for this summer 

 visitor, which does not usually reach us until towards the 

 end of April.— Philip W. Loten, Easington, Yorkshire, 

 March 6th, 1901. 



The Little Dusky Shearwater {Puffinws assiiv.ilis, 

 Gould'i in Sussex. — At the meeting of the British Ornitho- 

 logists' Club, held on February 13th, a eommunicatiou from 

 Mr. Ruskin Butterfield on the occurrence of a Shearwater 

 of this sjjecies in Sussex was read by Mr. Hartert. The 

 bird was picked up in an e.xhausted condition on the beach 

 near Bexhill during the hard gale from the W.S.W. on 

 Decembei- 28111, 1900. Both Mr. Ernst Hartert and Mr. 

 Howard Saunders have examined the bird, and proclaim 

 it to be Piijfiinig asiiwilis. This species breeds on the 

 islets of the Madeirau group, the Salvages, nearer to the 

 Canaries, and also in the Caj)e Verde Islands. It is also 

 found in the Aiistralian and New Zealand seas. This is 

 but the third occurrence of the bird in the British Isles, 

 which indeed are far from its normal haunts, and the 

 visits of this bird to this country can only be put down to 

 accident. 



Taini)/ Oii-l in Ireland [Irixh Nati'i-ali.if, March, 1901, p, 72), — Iq 

 Knowledge for Febvuarv, IflOl, p. t3. a record of Ihc occurrence of 



