588 



NATURE 



[October 19, 189^ 



publishes an almanack in which the weather predictions 

 are given a year in advance, and to judge from the adver- 

 tisement, these predictions have met with a ready circula- 

 tion. Further than this, it is mentioned with pardonable 

 pride, that when the gifted author was in need of a micro- 

 meter for the prosecution of his studies of these sun-spots, 

 a generous and a sympathising pubhc subscribed 700 

 francs with a readiness and devotion that should attest 

 the usefulness of his labours and his popularity. With 

 these advantages on his side we feel the responsibility of 

 venturing to disagree with him, or of questioning his 

 figures and his results. Nor is any hope entertained of 

 convincing him of the inadequacy of his arguments, and 

 some apology is perhaps due for pointing out one or 

 two facts which, if they do not convict the reverend Abbd 

 of misrepresentation, exhibit at least a want of candour, 

 which we should not have expected to meet in one of his 

 sacred calling. We may pass over his first argument 

 resting on sun-spots, because it is not impossible but that 

 these do exercise an influence on our atmosphere not yet 

 explained, though we are certain that the warmest 

 adherent of such a theory will find little additional sup- 

 port from the arguments stated by the Abbe. It may not 

 be possible to do justice by a translation to the words 

 " opposition constante et prolong^e," as applied to Venus. 

 By " opposition " is evidently meant superior conjunction, 

 but why constant and prolonged ? The superior con- 

 junction of Venus did not take place till the beginning of 

 May, and we regret to say that the words "coincident cette 

 annee 1893 avec les mois de Mars et Avril " (p. 46) are 

 unwarranted and misleading. The same remark applies 

 to the words (p. 90), " Vdnus ne se rapprochait de sa con- 

 jonction qu' en Juillet," and it may further be remarked 

 that since Venus was approximately at the same distance 

 from the earth in the beginning of July as at the beginning 

 of March, June ought to have been included in this " con- 

 stant and prolonged opposition." Again, with regard to 

 the moon's apse, it is declared (p. 90), "il arrivait encore 

 que I'apogde se faisait juste en pleine lune, et le perigtfe 

 a la nouvelle lune." A comparison of the dates of new 

 and full moon with those of perigee and apogee shows that 

 the Abbe is not more accurate here than in his remarks 

 on Venus. The average deviation for the three months 

 under notice is two and a half days, and in one case 

 the time of full moon was March 31, igh , while the 

 apogee did not occur till April 5, yh., or a difference 

 of time of four and a half days. But the curious and to 

 some extent the most interesting feature of the whole is, 

 that the admirers of the Cure will still continue to regard 

 him as an authority, and, what is more to the purpose, 

 eagerly purchase his almanacks, and would continue to do 

 so even if his errors were more palpable — more numerous 

 they could scarcely be. 



The remedy which the gifted author would apply to 

 prevent a recurrence of the ill effects which have made 

 themselves felt this year consists in an extensive system 

 of irrigation. Doubtless financial considerations would 

 enter in a perplexing manner into such a scheme, and 

 prevent it becoming a part of practical agriculture. But 

 the knowledge of local circumstances which the Abbd 

 probably possesses, and certainly we do not, permits him 

 to speak with an authority we do not like to question. 



W. E. P. 

 NO. 1251, VOL. 48] 



OUR BOOK SHELF. 



Geological and Solar Climates : their Causes and Varia- 

 tions. A Thesis. By Marsden Manson. (London : 

 Dulau and Co., 1893 ) 

 Several thinkers have from time to time set to work to 

 enlighten their fellow-creatures on the subject of the cause 

 of the Ice age, a period when ice covered quite generally 

 both the temperate and the tropical areas. Each one has 

 in his own way added something towards the solution of 

 this problem, whether that something was large or small, 

 but the theory that will produce conviction in all minds, 

 or rather in the majority of minds, has yet to come. The 

 causes which have been suggested are many and varied. 

 Some say the age was due to a decrease in the original heat- 

 ing of the globe ; changes in the elevation of the land, and 

 therefore varied land and water distributions ; changes 

 in the position of the axis of the earth ; while others 

 account for the phenomenon by suggesting a period of 

 greater moisture in the atmosphere ; variations in the 

 amount of heat radiated by our sun ; variations in the 

 absorbing power of the sun's atmosphere ; variations in 

 the temperature of space ; coincidence of an Aphelion 

 winter with a period of maximum eccentricity of the 

 earth's orbit ; a combination of the last mentioned nith 

 that of changes in the elevation of the land ; and lastly, 

 the explanation recently put forward by Sir Robert 

 Ball. 



In the present thesis the author, after reviewing briefly 

 the suggested explanations, goes back to the idea of the 

 decrease in the original heating of the globe, and on that 

 builds up a very plausible theory. To state briefly this 

 theory, one must mention that two sources of heat were 

 at work — first that of the resident or internal heat of the 

 earth, and second that of the sun. As the earth passed 

 from the era in which its climates had been controlled by 

 internal heat to one in which solar heat predominated, 

 uniform climates "must have been passed through during 

 which isotherms were independent of latitude." Before 

 the era was reached at which the sun had complete 

 control over the climates, the author says the continental 

 areas must have been glaciated, independent alsj ot 

 latitude. 



To state in so many words the direct cause of the Ice 

 age, he says that it is due to the remarkable properties of 

 various forms of water in relation to heat and cold. As 

 vapour it played an enormous part in the loss and receipt 

 of heat by radiation, as water it was the last to retain 

 " the effective remnant of earth heat, on account of its 

 high specific heat, and as ice it was able to store a great 

 amount of cold." 



The author then deals in detail with the way these 

 three forms of water played their part in this stupendous 

 phenomenon. 



The end of the Ice age was brought about so soon as 

 the solar heat could find its way to the earth's surface ; 

 the air being cleared of obscuring clouds and fogs by the 

 chilling of the oceans and the glaciation of continental 

 areas. 



The first zone over which the solar energy would first 

 establish its power would be the torrid zone ; travelling 

 polewards the glacial conditions would gradually be 

 removed upon lines parallel with the present isotherms. 



More on the subject need not be said here, but we would 

 recommend any one who takes an interest in this prob- 

 lem to give this book a perusal, for although there may 

 be many who would not agree with the writer in all 

 points, yet he has made an honest and plausible attempt at 

 suggesting a cause of one of the most difficult and yet 

 most fascinating problems with which we have to deal. 



A Manual of Electrical Science. By George J. Burch. 



(London : Methuen and Co., 1893.) 

 Of the many useful volumes in the University Extens'on 

 Series published by Messrs. Methuen, this is one of the 



