2l8 



NA TURE 



[January 4, 1894 



is disposed to regard the dark raarkings, in which the red 

 spot would be included, probably, as the real surface of 

 Jupiter, seen through an unobscured atmosphere, and the 

 position of the belts on Jupiter is thought to support 

 the suggestions of the author. But we doubt whether 

 astronomers are agreed that the dark markings represent 

 clear sky, and the lighter portions cloudy vapour. Mars 

 would seem to be the one planet in which we might ex- 

 pect i-O find atmospheric conditions similar to those here 

 prevalent ; but we are told that there are " probabili- 

 ties based upon scientific reasons, that the clouds upon 

 Mars are not distributed in the same manner as upon the 

 earth." Though when we consider what a presumably 

 comparatively unimportant factor the solar heat is upon 

 Jupiter, and that, moreover, the axis of rotation is nearly 

 perpendicular to the plane of the orbit, on a superficial 

 view, this observation seems to be more applicable to 

 Jupiter than to Mars, From the remark with which the 

 paper closes, we gather that the author intends to pro- 

 secute this subject of investigation on the planets. We 

 wish him success. 



Of the second work mentioned at the head of this 

 notice, it is rather difficult to speak. Although the author 

 has not sketched the plan and scope of the work in any 

 introductory chapter, it is easy to understand the prin- 

 ciple that has guided him in the construction of the book. 

 He has evidently been at great pains to bring together 

 all that is valuable, or that he thought valuable, in the 

 descriptions that have been given of hailstorms in the 

 past, not only in the accompaniments of the hailstorms, 

 or of the characteristics of the hailstones themselves, 

 but also of the theories that various authorities have 

 suggested to explain their occurrence. When we con- 

 sider that in the case of nearly every hailstorm, some one 

 is found to describe it, it is evident that the materials from 

 which Mr. Russell can draw his information are very 

 widely scattered. The list of authors quoted is a long 

 one, and could no doubt have been made much longer, 

 did not the reiteration of the same facts become weari- 

 some. Having collected his information, the author has 

 attempted to digest it, and has given us a summary of 

 the characteristics of hailstones with a graphic descrip- 

 tion of the development of a hailstorm. One consequence 

 of this method of dealing with the subject is that about 

 three-fourths of the book consist of extracts from various 

 authors, and only the remainder is original matter. This 

 class of work, if not very brilliant, is, no doubt, valuable ; 

 and inasmuch as most of the extracts are given in the 

 words of the author, with distinct references to the sources 

 from which they are taken, this book may save much 

 searching of original authorities, and a proportionate 

 saving of time. Whether the materials are arranged in 

 the most advantageous manner, is a question about which 

 some doubt may be entertained. It would seem some- 

 times as though the extracts had been printed in the 

 order in which they had been encountered, without any 

 attempt at arrangement at all. To take the first chapter, 

 " descriptions of hailstorms and hailstones," at first sight 

 it would look as though some chronological order was to 

 be maintained, for we begin in 1680, and pass next to the 

 early years of this century ; but when we get into the 

 middle of the century, we flounder about from 1890 to 

 1870, and back again, without any guide. Neither is 

 NO. 1262, VOL. 49] 



locality any rule, for we are taken all over the world, 

 without method or system. Nor is it easy to trace any 

 gradual scientific progress in the descriptions. We have 

 simply more or less complete descriptions of some fifty 

 hailstorms, or of the salient features that distinguished 

 them. 



The second chapter gives us observations of tempera- 

 ture, clouds, and winds at great altitudes, principally 

 confined to the accounts of balloon ascents. In this 

 chapter, which is very short, there might have been found 

 room to discuss in more detail the observations made at 

 some of the meteorological stations at considerable alti- 

 tudes. The results obtained at Pike's Peak, Colorado, 

 would seem to be of the highest importance in this con- 

 nection ; but the author prefers to drop this topic, though 

 apparently germane to his subject, in order to discuss, or 

 rather to collect, the opinions and observations of those 

 meteorologists who have noticed the connection of elec- 

 tricity with the occurrence and formation of hail. 



The chapter on theories of hail is interesting. In it is 

 given the opinions of most of those whose opinions are 

 worth recording, but in the popular and not the scientific 

 language which some of the authorities quoted would 

 have used. Von Bezold especially suffers from inadequate 

 description, and, if we are not mistaken. Hertz's name is 

 not mentioned. It would seem almost as though the 

 author were not acquainted with much of the hydro- 

 dynamical analysis that has been applied to the atmo- 

 sphere, or being acquainted with it, disapproves of its 

 application to the present inquiry. 



In the chapter on the development of a hailstorm, 

 objection will probably be taken to the insistance and 

 stress that is laid upon the part played in the mixture of 

 air of different temperatures, as a primary cause in pro- 

 ducing precipitation, whether it be of hail or any other 

 form of moisture. The numerical example worked out 

 to illustrate the author's point is not very clearly ex- 

 pressed ; and even granting the figures of the author, he 

 is obliged to fortify his case by a continual mixture- 

 But the continual mixture would tend to produce uni- 

 formity of temperature, and disturb the accuracy of the 

 original calculations. Undoubtedly we have present, in 

 what it is usual to call the hail stadium, an ainount of dry 

 air which it is convenient to separate, in theory at least, 

 from the saturated vapour also present, the drops of 

 water, and the particles of ice or snow which probably 

 constitute the germ of the large hailstones, and then, if 

 the conditions are favourable, we get hail ; and it is diffi- 

 cult to see that our author has carried the explanation 

 much further. Nor possibly does the application of the 

 mechanical theory of heat, however legitimate its 

 methods may be, advance our knowledge very materially, 

 at least in a practical direction. The local, and often 

 confined, area over which hailstorms occur, is a marked 

 feature of their occurrence, and is likely, for a long time 

 to come, to baffle the applications of a general theory, and 

 prevent any sufficient precautions being taken against 

 the damage they produce, which it maybe supposed is 

 the practical outcome that sufferers hope to derive from 

 the studies and inquiries of meteorological observers. 



In the final chapter, headed " Conclusions." there is an 

 attempt to gather up the results of the observations 

 recorded in the previous chapters. It is a pretty fair 



