534 



NA rURE 



[Apn/ 7, 1887 



more powerfully on particles of ice than on drops of water. I 

 ventii;e to offer the following suggestions. 



Ltt IS CO isider what happens when an ice cloud is forming. 

 Dust particles, no doubt, .act as nuclei to ice crystals as well as 

 to water drops j so that a number of crystals will start into 

 existence about the same time. Soon there will be no more 

 dust particle) of sufficient size to form nuclei. The rate of de- 

 position on a crystal will be proportional to its surface, so all the 

 crystals will grow in diameter at the same rate. The ratio of 

 the largest diameter to the smallest will become less. In fact 

 the crystals \\ ill become more uniform in size. No doubt, too, 

 the supply of aqueous vapour near a large crystal will be con- 

 sumed mere rapidly than it can be refunded by diffusion. So 

 the larger c^7^:tals will grow fomewhat more slowly. These are 

 causes tending towards uniformity. They account for the 

 observed fact that they are newly formed clouds, whicli show 

 the brightest colours, though when they first come into view 

 they are white. It is easy to give reasons why some clouds 

 should lose their colour so soon. Varying conditions may affect 

 the growth of diflerent layers of particles in a different manner, 

 or a slight increae in the rate of deposition may call new dust 

 particles into action. 



In the case of water clouds there are two special causes 

 brought into action against uniformity. Sir William Thomson 

 has shown that the maximum vapour-tension at the surface of 

 water is largely increased when the surface is highly convex. So 

 the large drops will grow moi'e rapidly th.an the small ones, and 

 the range of size will be more and more extended. Secondly, 

 whenever two drops of water come into collision, they will com- 

 bine into one larger one. 



In conclusion I may remark that St. Moritz is 6500 feet above 

 sea-level, and the iridescent clouds were generally above the 

 surrounding mountains, i.e. at least 11,500 feet above sea-level. 

 On some days the sky was overspread at a great height, with a 

 thin haze gathered here and there into denser streaks (cirro- 

 stratus ?). The haze sometimes formed coronre clo e ■ around 

 the sun. I have not made out more than two spectra. From 

 rough measures of the diameters of the rings, I find for the 

 diameters of these filaments values varying from '04 mm. to 

 •07 mm. James C. McConnel 



St. -Moritz, Switzerland, March 14 



Aino Hairiness and the Urvolk of Japan 



In Mr. B, 11. Chamberlain's remarkable and instructive 

 monograph on the Ainos, contained in the first number of the 

 Memoirs of the Literature College of the Imperial University of 

 Japan, just published, will be found an explanation of the 

 different conclusions that have been arrived at by different 

 observers as to the hairiness of that singular people, equally 

 isolated, so far as our present knowledge extends, by 

 language and by physical characteristics from all surrounding 

 races. When I spent some days among these so-called 

 savages in 1S65 or 1S66, I had the opportunity of examining 

 some four or five score of them, ch efly men, and in every indi- 

 vidual I found the phenomenon of hairiness more or less 

 marked. The sternal, inter-scapular, and gluteal regions were, 

 in particular, thus provided with a natural covering, the very 

 regions where such a protection from the drip of rain would be 

 most serviceable. I remember well that in some individuals the 

 gluteal fur was so abundantly developed that thick tufts of hair, 

 several inches long, could be grasped in the hand. But recent 

 travellers have been struck by the number of natives they met 

 with deficient in hairiness — whether they were proportionately 

 lacking in face-hair is not stated — and it has been doubted 

 whether hairiness is really an Aino characteristic. Dr. Baelz's 

 investigations have, however, amply vindicated the claim of the 

 Ainos to be the hairiest people in the world, and now Mr. 

 Chamberlain shows that the smooth-bodied natives are in fact 

 half breeds, the progeny of native mothers by Japanese fathers. 

 Unions of this kind have probably increased in frequency during 

 the last two decades. Between the two races, however, some 

 incompatibility seems to exist, for their progeny exhibit a dimi- 

 nished fertility. " The second generation," says Mr. Chamber- 

 lain, on the authority of the Rev. Mr. Batchelor, who has lived 

 for years among the Ainos, and contributes an exhaustive 

 grammar of their language to the volume of Memoirs before me, 

 " is almost barren ; and such children as are born — whether it 

 be from two half-breed parents, or from one half-breed parent 

 and a member of either pure race — are generally weakly. In the 

 third or fourth generation the family dies out." 



The injury to the reproductive system caused by this 

 "miscegenation "—a phenomenon not unparalleled in the history 

 of man, and proving the existence in man, as in other organisms, 

 of a tendency to specific variation — has an important bearing 

 upon the much-debated question of the proportion of Aino lilood 

 that runs in the veins of the Japanese of to-day. Mr. Chamber- 

 Iain, chiefly from philological con.-iderations based upon an 

 examination of place names, arrives at the conclusion that the 

 Uivolk of the Japanese group, from the extreme south to the 

 furthest north, was an Aino race, and we know from history that 

 up to the time of Yoritomo (twelfth century A.D.), and probably 

 later, the northern half of the main island was still, to some extent, 

 peopled by Ainos. Yet even the northern Japanese are smooth- 

 bodied, although it is extremely unlikely that " miscegenation " 

 did not obtain between their Japanese ancestors and the 

 aborigines. In the light of Mr. Batchelor's observations the 

 explanation of this apparent anomaly is e.asy. The half-breeds 

 died out, and the prepotency of the Japanese in numbers and 

 civilisation gradually expelled the Aino element from the popu- 

 lation, wdiich has thus become an almost purely Japanese one. 



It must not, nevertheless, be forgotten that at least two dis- 

 tinct races may still be traced in the existing population of the 

 Japanese group. One is slim, high-headed, and often aquiline- 

 nosed ; the other stouter and broader, more brachycephalic, and 

 Hat-nosed. Excellent types of both, especially of the first, will 

 be found in Siebold's " Nippon Archiepf." '1 he former consti- 

 tuted the military class of Old Japan, the latter the pea-antry ; 

 and of the latter some degree of hairiness of the limbs is a not 

 uncommon characteristic. The drawings of Hokusai sufficiently 

 prove this assertion, which the experience of every resident in 

 Japan will confirm. It may the: efore be safely assumed that the 

 elimination of the Aino element has not been complete. For 

 my own part I believe that the earliest inhabitants of Japan were 

 tribes of Malayo-Polynesian blood coming from the south, and of 

 Aino blood coming from the north. Altaic immigrants followed, 

 and, partly perhaps through some degree of reproductive pre- 

 potency, gave a characteristic and predominant stamp to the 

 population without total elimination of its aboriginal elements. 



University of London, March 21 F. V. DiCKlNS 



Units of Weight, Mass, and Force 

 H.wiNG read with much interest Prof. Greenhill's letter in 

 Nature of March 24, p. 4S6, I am inclined to think that much 

 of the perplexity felt by .some who begin the study of dynamics 

 arises from the want of names for the units of the various mag- 

 nitudes with which the science deals. We have names for units 

 of time, space, mass, force, work ; but no names for units of 

 Velocity, acceleration, impulse, momentum, &c. I venture to 

 suggest the following : — Let the unit velocity he that with which 

 a point describes uni'brmly one foot per second. Let this unit 

 be called a vel. Let the unit acceleration be that whereby 

 the velocity is uniformly changed by one vel per second. Let 

 this unit be called a eel. Then everything liecomes clear. E.g. 

 the meaning of the equation W = i»g is seen to be this : 

 The weight of a mass of m pounds at a place where the accelera- 

 tion arising from the mutual stress between it and the mass of 

 the earth is g eels being IV poundals, the iiiimlitrs W mg are 

 connected by the equation 1V= m^. Then, for the sake of the 

 beginner, let the names of the units be given thus : W = mg 



poundals, >ii = — pounds, g = — eels. It is too common to 



g m 



see acceleration expressed in feet per second, instead of in vels 

 per second. If the weight of a mass of m pounds be defined to 

 be the mutual stress between it and the mass e pounds of the 

 earth, it is evident thnt the weight of e attracted by m is the 

 same as the weight of m attracted by e ; and, in the absence of 

 either, the other would have no weight. 



Bardsea, March 29 Edward Geoghegan 



The Earthquake in the Riviera 



Though there can be no question as to the amount of damage 

 done by the late earthquake — I am writing in a shed, the hote 

 being destroyed — I think that the violence of the shock has 

 perhaps been very greatly exaggerated. I have only been able 

 to make a flying visit to this place and to Diano Marina, but I 

 cannot help being struck by the fact that the peculiar archi- 

 tecture is the main cause of the large amount of destruction^ 



