i 9 4 



NA TURE 



[Jan. i, 1885 



in Japan. In all these, as well as in llie case of the hills m ai 

 Freiburg mentioned by Dr. Wetterlian, the soil appears to be a 

 porous detritus with a hard substratum. At St. Anton, as at 

 Chamounix, the hill-side sloped at an angle of about 50 , with a 

 northern aspect, and in both cases and in Japan the phenomenon 

 occurred in the autumn, a season often characterised, especially 

 at high elevations, by cold nights and genial days. Dr. Koch 

 calls it " smderbar" and "gam eigenthiimlich," and it is 

 plainly not of common occurrence. 



Dr. Koch's explanation of the phenomenon is virtually the 

 same as had occurred to me, except that both he and I >r. 

 Wetterhan appear to consider that the water was derived by ab- 

 sorption from a moist atmosphere. In none of the descriptions, 

 however, is there any mention nf what was one of the 1110 t 

 striking features of the ice which I tried to describe, viz. iis 

 division into distinct layers, each layer being of uniform depth ; 

 and this, showing as it does that the crystallisation was inter- 

 rupted, and not continuous, seems to make it more probable that 

 the water was supplied from- below. The cylindrical perfora- 

 tions were, no doubt, caused by the presence of pebbles or small 

 lumps of earth too dense to allow the ice-crystals to penetrate 

 them, and too heavy to be pushed up. The layer of dust on the 

 surface was much thinner in my case than in Dr. Koch's, which 

 was no doubt due to accidental difference in the soil. 



A friend in the country tells me that on a bright winter's day 

 two or three years ago he picked up a piece of a dead beech- 

 branch which was covered with filamentous ice, such as is de- 

 scribed by the Duke of Argyll and others in Nature (vol. xxi. 

 PP- 2 74. 3 02 )- He brought it home, and, having examined it, 

 left it out in the sun, when the crystals of course soon vanished. 

 Next morning, however, he was surprised to see that they had 

 all reappeared as before. The water from the melting ice had 

 again filled the pores of the wood, and again been extruded in 

 the same crystalline form. Now, if the highest temperature to 

 which they had been exposed during the diy had been 32 F., 

 and a fresh supply of water had been afforded from any source 

 to the wood, then neither would the ice have melted nor the 

 water frozen ; until the temperature fell again at night, when a 

 fresh formation of crystals would have taken place, which would 

 have pushed rip those previously existing, and the result would 

 have been a formation similar to that described in my letter. It 

 seems more probable, therefore, that the moistening took place 

 from below, as I suggested. 



Hampstead, Decembei 20, 1SS4 I;. Woodd Smith 



Lightning in the Tropics 



My experience confirms the remarks of Dr. Von Danckel- 

 manin Nature (p. 127) respecting the little damage done by 

 lightning in tropical climate-. 



In the plains of India at the commencement of the monsoon, 

 storms occur in which the lightning runs like snakes all over the 

 sky at the rate of three or four flashes in a second, and the 

 thunder roars without a break for, frequently, one or two hours 

 at a time. During twelve years' residence in India I heard of 

 only two human being- and, I think, three buildings being 

 struck, although in part! of lower Bengal the population 

 amounts to more than 600 to the square mile. I always attri- 

 buted the scarcity of accidents to the great depth of the stratum 

 of heated air next the ground keeping the clouds at such a height 

 that most of the flashes pass from cloud to cloud, and very few 

 reach the earth. This idea is supported by the fact that in the 

 Himalayas, at 6000 feet or more above the sea, buildings and 

 trees are frequently struck. I have seen more than a dozen pine- 

 trees which had been injured by lightning on the top of one 

 mountain between Sooo and 9000 feet high. In the British 

 Islands thunderstorms ire said to be more dangerous in winter 

 than in summer, and such a fact, if Hue, can be explained by the 

 very thin stratum of air then intervening between the clouds and 

 earth. J. J. Meyrjck 



London, December 19. 1SS4 



An Unnoticed Factor in Evolution 

 I am surprised that the letter of Mr. Catchpool in Nature 

 (vol. xxxi. p. 4) has remained unnoticed by your correspondents. 

 His hypothesis that mutual sterility may be the cause, not the 

 remit, of specific divergence, is, I think, quite in accordan 

 with many observed facts. The buffalo and the ox, the sheep 

 nd the goat, have lived foi age- side by side without, as far as I 



am aware, a hybrid between either of them having been pro- 

 duced. Mule or hinny hybrids between the horse and the ass 

 are obtained easily, but the offspring is rarely fertile, so rare, 

 that the British Consul at Granada told me, when I was there, 

 that he had never known of a case, although in Spain mules 

 exist in thousands. Amongst bovine animals many species pro- 

 duce hybrids which are apparently perfectly fertile; those 

 between the Indian ox and the gayal, species of different genera, 

 Bos and Bibos, are common, and their fertility is shown by the 

 existence of numerous intermediate hybrids. There is living at 

 the Zoological Gardens at the present time, a hybrid between 

 the Indian ox, the gayal, and the bison, and, by her side, a 

 hybrid between herself and a bison. The offspring of the cross 

 between many species of ducks are perfectly fertile. This I 

 have repeatedly seen in the case of the hybrids between the 

 tufted duck and the pochard. I- think there is another unno- 

 ticed factor in evolution. The scent of animals plays an im- 

 portant part in their sexual relationships, and "sports" in this 

 respect are as likely to occur as in the organs of the body ; thus 

 the peculiar odours of the sheep and the goat may be mutually 

 repulsive. J. Jennek Weik 



Chirbury, Beckenham, Kent, December 15, 18S4 



A Large Meteor 



A MAGNIFICENT meteor was oberved here last night. Its 

 path lay from the west of a Hydra? towards the west of ij Mono- 

 cerotis. Its head could not exactly be said to explode but broke 

 up and extended suddenly considerably along its course, emitting 

 a deep red and bluish white light, the latter of a most extra- 

 ordinary brightness, for a moment quite sufficient to allow print 

 to be discerned. It disappeared very near Ilh. 19m. 6s. M.T. 

 Dublin, and left a bluish white trace behind it, which could still 

 with certainty be perceived seventeen minutes after the meteor 

 hid disappeared. Otto Boeddicker 



Birr Castle Observatory, December 23, 1S84 



THE FORMATION OF THE SOLAR SYSTEM* 

 THE aspect of the heavens, the appearance of the 

 J- planets, do not give us the least idea of the solar 

 system. In order to understand it well, we must in 

 imagination quit our world altogether, and remove our- 

 selves to a distance, so as to embrace in one glance 

 the little system of which so ordinary a star as our sun 

 occupies the centre. 



Around the sun there move eight primary plinets at 

 very unequal distances. Of these planets six have 

 satellites ; that is to say, they in their turn arc centres of 

 little systems reproducing the solar system in miniature. 

 Thus the Earth has a satellite, the moon ; Mars has two, 

 Jupiter four, Saturn eight, Uranus four, and Neptune, the 

 most distant, has one. A striking thing in this system, 

 that which makes it unique, is that the sun turns on its 

 own axis from right to left, and all the planets with- 

 out exception revolve around it in the same direction, 

 almost in the same plane, that of the rotation of the sun, 

 and describe orbits very nearly circular. 



Would not one say that a vast gyratory movement 

 animates all these bodies, and that the secondary systems 

 of the Earth, Mars, Jupiter, &c, are little whirlpools 

 moving in the primary one? Such was the idea of 

 1 le 11 .Hies. If the solar system does not actually consti- 

 tute a whirlpool, it was originally formed by a movement 

 of this nature in the nebula winch gave it birth. 



The sky exhibits here and there a large number of 

 gigantic masses of extremely rarefied matter, like the 

 mists of chaos, without shape, having undergone only 

 that degree of condensation necessary to create a feeble 

 light. We require usually a powerful telescope to distin- 

 guish them, and then we can see them by thousands in 

 the heavens ; these are nebula. 



When you visit an observatory under the escort of an 

 astronomer whom you know, tell him several days before- 

 hand that what you wish is not to gaze at the moon, or 

 the planets and their satellites, or the fixed stars, double 



1 Translation of an article by M. Faye In a recent number of U Astronomic. 



