3i6 



NATURE 



[February 2, 1893 



Bridge— and to students having no access to a laboratory 

 little satisfaction will be given when told : " The details 

 of the construction and practical use of the different 

 forms of Wheatstone's Bridge used in the measurement 

 of resistance are best learnt in the laboratory, and for 

 this reason we shall not give any further description of 

 the arrangement." 



In many instances the student is driven through a 

 mass of theory before he has a fair idea of the general 

 phenomena ; thus in the introductory chapter on " Cur- 

 rent Electricity," after a six-line description of a simple 

 cell and current, over two pages are occupied in proving 

 that the effects produced could be explained by the dis- 

 sociation and procession of the hydrogen and oxygen 

 atoms. The work is generally remarkably free from 

 errors and misprints, but one occurs in the explanation 

 just mentioned. The attraction of zinc for oxygen is 

 said to be much greater than that of the copper, while 

 later the zinc is also considered " to repel hydrogen less" 

 Here, and in many other instances, the words to be em- 

 phasised are printed in italics. Another mistake will be 

 found on pp. i68 and 169, where in comparing, by the 

 method of oscillations, the.field due to a magnet with that 



of the earth, the author starts with the equation ■ *" = — L 



I «■' 



instead of -^^ =— '-i and reasoning correctly from this 



false hypothesis, he deduces false results, while the 

 answer to Ex. 8 on this part of the subject appears incor- 

 rect. Fig. 13, p. 201, in illustration of Oerstedt's experi- 

 ment, is not correctly drawn. 



The arrangement of "calculations" and examples at 

 the end of each chapter must prove extremely useful to 

 students possessing beforehand an elementary knowledge 

 of the general phenomena, and to such, rather than to the 

 very beginner, the book may be commended. H. S. J. 

 Manners attd Monuments of Prehistoric Peoples. By 



the Marquis de Nadaillac. Translated by Nancy Bell 



(N. D'Anvers). (New York and London : G. P. 



Putnam's Sons, 1892.) 

 A BOOK summing up in a popular style all that is now 

 known with regard to prehistoric man would probably be 

 welcomed by a tolerably large class of readers. The 

 present work does not quite supply the kind of summary 

 that is wanted. The author does not distinguish with 

 sufficient clearness between the various periods with 

 which he deals ; he indulges too freely in talk of a vaguely 

 moralising tendency ; and some of his statements do not 

 accord with the conclusions of the best authorities. Speak- 

 ing of the Round Towers of Ireland, for instance, he says, 

 " According to the point of view of different archaeologists, 

 they have been called temples of the sun, hermitages, 

 phallic monuments, or signal towers." The reader is thus 

 left to suppose that the question is still open, whereas all 

 competent students of the subject accept the theory of the 

 late Mr. Petrie, a theory which the Marquis de Nadaillac 

 does not even mention. However, the author has presented 

 a large number of interesting facts in the course of his 

 exposition, and there are occasional passages in which he 

 brings out very well the attractive elements of some of 

 the more fascinating departments of archaeology. 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications. ^ 



Two Statements. 

 In a letter addressed to the Daily Chronicle, dated January 

 25, 1893, Prof. Karl Pearson makes two statements respecting 

 my opinions and grounds of action : 



NO. I 2 14, VOL. 47] 



" As in society at large, so in academic matters, his mode of 

 insuring progress is unlimited individual competition," 

 and again : 

 " he is an individualist in all matters." 



Seeing that in an essay "On Administrative Nihilism," pub- 

 lished twenty-two years ago ; and iu another on " Government : 

 Anarchy or Regimentation," published in 1890, I have done my 

 bestto combat the doctrine Prof. Pearson attributes to me, I shall 

 be glad to know what justification he has to offer for so grave a 

 misrepresentation. The purpose of it is obvious. 



T. H. Huxley. 



Hodeslea, Eastbourne, January 29. 



A Meteor, 



The following is taken from the Pretoria Weekly Press for 

 January 7 : "A few evenings ago a meteor of unusual size and 

 brilliancy was observed at Bloemfontein shooting right across 

 the eastern sky. It looked like a rocket of a greenish colour, 

 and burst in a shower of sparks in the south-east. The spec- 

 tacle was much admired by those who were fortunate enough to 

 witness it." 



This meteor, as seen in South Africa, appears to have had 

 many points in common with a similar one seen in England 

 about the same time, and reported by several observers in the 

 daily Press. W, L. Distant. 



Purley, Surrey, January 31, 



"Hare-lip" in Earthworms. 



Attention has recently been drawn by Prof. Andrews 

 {American Naturalist, September, 1892) and myself {Science 

 Gossip, 1892) to some abnormal conditions of life among the 

 terrestrial annelids. I have now to place on record a totally 

 new appearance, which is, I think, very aptly expressed by the 

 term "hare-lip." The worm which I have had under exam- 

 ination presented the peculiarity figured below, and whe n alive 

 and in motion suggested to my mind most forcibly the appear- 

 ance which we associate with the name I have adopted. 



The specimen in question belongs to the genus Allolobophora, 

 in which genus, so far as my experience goes, almost all the 

 abnormalities are found. The genus Lumbricus, it should be 

 observed, is very seldom, if ever, known to present any of 

 these peculiarities. Hitherto the Long worm {A. longa, Ude) 



Diagram of the anterior portion of green-worm {Allolobo/>hora chlorotica. 

 Savigny), showing abnormal appearance of lip (;>r), peristomium iper), 

 and three succeeding segments, seen from above, and enlarged. 



has been most prolific of bifurcated heads and tails. Now we 

 find the Green worm {A. chlorotica, Savigny) yielding new 

 features for study. The peculiarities which have presented 

 themselves in former times have usually taken the form of a 

 second head or a supernumerary tail. In this instance there is 

 no off-growth, however, but merely a malformation of the 

 anterior segments. One might have supposed that the pecu- 

 liarity was due to accidental causes. It would have been easy 

 to suppose that the head had been split, and then the wound 

 had healed, leaving a seam down the middle. I observed, 

 however, that each of the three specimens of the Green worm 

 which I received from Cork (Ireland) showed some abnormal 

 feature, and there were other peculiarities in this particular 

 specimen which indicated that we had to deal with a congenital 

 rather than an accidental condition of things. 



