292 



• KNOWLEDGE • 



[Fkii. .», 1882. 



tion " wnn« rapri««nt«d hy tho Himilar aoundii, " imlrfido" 

 " lemtrtitii," and " r/trrir/o," thi-v woro rppreaontcd on tho 

 first ooiTi'iion liy tho utterly dixsimilnr sounclg " emvlraU'," 

 " tinknintrai," aiul " MoinbrcUUi." This pativiit ktu-w 

 whon he xpok)' wrongly. 



lUbi'ftosJ. 



RCIEN'CE LADDEllS.* 



rnmCSE little iKjoks arc i-apital. Thoy deal in the 

 1 ]iliiincst |)ossil)l<' words with thi'ir ri'spcctivo .sulyccts, 

 hut what tlipy dcsctilrt- they di-.scril)c neatly and exactly. 

 Tlipy arc suited for thn youngest readers, yet they contain 

 a uunib'i' of facts which many who are not very young will 

 Gad full of int«--re8t. Even those who know most of the facts 

 oontjiiu' rl in these lHX)ks will enjoy reading them simply 

 liocause of the pleasant way in which tlie facts arc i)re- 

 wntod. 'J'nke, for instance, the following account of the 

 way in which hydras arc born into the world. For a long 

 timo no one knew. " At last, however, a patient natu- 

 ralist, who had long watched a hydra in a glass case, saw 

 tlie growth of a tiny egg on its body, below the mouth 

 and arms. Three days after the discovery of the egg, it 

 was loosened from the body of the mother, and fell to tho 

 bottom of the water. When it Hrst appeared it was 

 cream-colour ; it had now turned a bright orange. It re- 

 mained at the Ijottom of the water for lifty-fivc days, and 

 the only changes which took place in it during that time 

 were that the outside skin became rough and the shape 

 changed from round to oval. At the end of fifty-live daj's 

 the egg cracked, and a baby hydra ]>ushcd out part of a 

 soft, transparent, crystal-like body, quite round and 

 nmooth. Two hours afterwards this baby began to put out 

 threads, and in seven days its shape was just like that of 

 the mother hydra, only much smaller. This baby hydra 

 took no food till it was more than a month old. It is now 

 known that hydras do not always come from eggs, but 

 grow out like liranches from the bodies of grown-up 

 creatures. From these branches spring yet younger 

 branches, so that sometimes quite a family tree is made." 



SCIENCE FOR ALL.t 



The object of this work so closely resembles that which 

 we have in view in K.nowledce, that it would be strange 

 (considering who liave bien Dr. Brown's coadjutors) if the 

 work itself did not meet with our approval. In the present 

 volume, which is the fifth of the .Kcries, we find most 

 interesting articles by Dr. Wilson, on Zoological subjects ; 

 by Prof. Duncan, on Earthquakes and Animals, old and 

 now ; by Dr. Mann, on Lighting, Ac. : and by other 

 writers on subjects with which tlicy are respectively more 

 or less conversant The editor, Dr. Drown, discusses ably 

 the question how plants were distributed over the earth. 

 Mid in another article considers the question, What is a 

 fruit t 



Nearly all the articles are well written and well illus- 

 trat«-d— many, quite admirably. The volume, as a whole, 

 is a charming contribution to popular scientific literature, 

 well-printed on excellent paper, and handsomely bound. 



• Hcioiipo Lndders. Series I. No. 1.— Forms of band and 

 Wiitir. 8rrio8 II. No. 1.— Vogi-tablc Life. Series III. No. 1.— 

 Uwost Porms of Water .\nimal«. By N. ri'Anvors. Price Cd. 

 iwcli. (boiidon : 8amp8uu I.mv, Marstun, i Co.) 

 ^ t acUnct for All. Kdited l,y Uobert Hrown, M.A. (Caasell. 

 IVttcr, i Ualpin, London, I'aru). and Nuw York.) Price 5a. 



Here and thero ore some shortcomings in stylo of treat- 

 ment, and occasionally, but more seldom, in scientific 

 accuracy. We may cit<', as instanciis of the latter kind, 

 Mr. Denning's stat'-ment that the Satumian rings, if solid, 

 may be maintained in equilibrium in the way Buggest*-d 

 by Laplace. Nothing can l>e more certain than that 

 the rings could not possibly be maintained in equi- 

 librium a-s I.jiplacc supposed. It i.s also not tru« 

 that most careful measurements .show the rings to be 

 slightly eccentric. Some measurements have done so on 

 particular occasion.s, that is all. It is clear, from Mr. Den- 

 ning's account of the appearance of the rings, as supposed 

 to be seen from the planet, that he has not given the matter 

 even that cursory examination which Dr. Liirdner ga\e it, 

 otherwise he would a.s8urcdly have seen that in the vicinity 

 of the poles no part at all of the rings could pos.'iibly be 

 seen. Nor is it true tliat at night the rings would be seen 

 as a vivid semicircle of light ; during the winter half of 

 each Saturnian year they would not bo visible. 



Apart from minor defects such as these, the volume 

 before us is one whidi, whether regarded as part of the 

 " Science for All " series, or judged by its intrinsic merits, 

 can be warmly recommended. It is full of interesting 

 matter, plainly worded, and, for the most part, exactly 

 described. 



THE SCIENCE OF THE STARS.* 



We admire Mr. Pcarco's calm andarity. He sends to as for 

 review a work on Astrology with as much confidence as if it were 

 such a work as *' The Courses of the Stars," by onr esteemed corre- 

 spondent Mr. Bazloy, a work bearing a title which mipht cause it 

 to bo confounded with astrolofncal treatises (instead of being one 

 of the most valuable contributions made during the last few years 

 to the science of tho stars), while Mr. Pcarco's book, instead of 

 justifying its title " Tho Science of the Stars;," advances gravely all 

 the absurdest views of the astrological charlat.in. 



Perhaps the most remarkable feature of this work is tho mixture 

 of literary lore and utter ignorance of science. We have references 

 to the sayings of a number of more than respectable writers, in 

 company with statements based on tho authority of such an 

 ignoramus (to speak charitably) as the late I^ioutcnant Morrison, 

 the Zadkiol of the notorious almanac bearing that name. One 

 specimen of the manner of reasoning adopted by modem astrologers 

 (the ancients had some reason for their errors) may be quoted — it 

 will sntEce, vfi} should imagine : — 



" It may ajipear arbitrary to take the moon as general significatrix 

 (in mundane astrology) of the common people. Yet it would seem 

 to have some show of reason when we remember that the Tay- 

 bridge catastrophe, by which nearly one hundred lives were lost, 

 only one or two of the passengers ranking above the class of 

 'common people,' took place on the very evening (Dec. 2S, 1879) of 

 the partial eclipse of the moon in the sign Cancer (which mlesl 

 Scotland). — aye, and before the shadow had entirely papsed away 

 from the moon's disc. Ramsey avers that such an eclipse falling in 

 Cancer denotes ' the death and slaughter of obscure, common,! 

 plebeian kind of people.' On July 12, 1870, a total eclipse of the 

 moon, visible in Europe, took place. Throe days afterwards Lo' 

 Napoleon declared war against Prussia. The slaughter in that 

 was horrible." 



THE EFFECTS OF TOBACCO. 



By Dr. Mcib Howie. 



PAET I. 



THE nse of tobacco is becoming so extensive, that it is inonml 

 bent upon all who are interested in the health of the comj 

 mnnity, to devote some attention to tho effect of such increa 

 consumption. How does tobacco affect the human organism ? 

 it increase or diminish its capacity for physical or mental work ( 

 Docs it tend to prolong life, or to bring on prenuituro decay ? Do 

 it make life, as a whole, more pleasant and agreeable, or are its oon 

 fortiug and soothing effects rendered nugatory by subseqnenl 

 irritability ? Many such questions naturally arise in the mind < 



• " The Science of tho Stars," by Alprkd J. Prabcr. 

 Marshall, & Co., London.) 



SimpE 



