March 3, 1887] 



NATURE 



4', 



"parlagcc dans Ic feu "—is not historic, Haiiy's and 

 Monteiro's name referring to the different fusibilities of 

 the two constituents of the spheroids. We doubt also the 

 primary origin assigned to the chalcedony with which the 

 hollows of these old rhyolites are so often filled. Here, as 

 is so frequently the case among Continental writers, the 

 immense importance of secondary changes appears to be 

 overloo';cd. In one of these lavas M. Noury has found a 

 spherulite measuring i8 inches in diameter. The " sphdro- 

 lithes," however, of certain diabase veins (p. 41) would 

 appear to correspond to the spheroidal structure of 

 weathered basalt rather than to the contemporaneous 

 volcanic bombs suggested by the author. 



The account of the connection between open fissures 

 and the decomposition of dykes, and of the origin of the 

 numerous bays, as well as of the larger inland features, is 

 full of interest to the visitor. In the review of the 

 history of the island the discussion of recent elevation 

 and depression is too lengthy to allow of justice being 

 done to the evidence relied on for the ages assigned to 

 the various types of rock — evidence derived solely from 

 comparison with the mainland of France. The scanty 

 preservation, moreover, of Secondary deposits in the 

 Hebrides makes one cautious in accepting the con- 

 clusion (p. 139) that Jersey has remained above water 

 since Permian times. M. de I.apparent has, indeed, 

 recently stated that the final conglomerate may be of 

 Triassic age. 



The book is written in the lucid and attractive style 

 that French men of science have taught us to expect. A 

 coloured geological map forms a handsome and valuable 

 addition. G. C. 



OUR BOOK SHELF 



General Biology. By William T. Sedgwick, Ph. D., and 



Edmund B. Wilson, Ph.D. Part I. Introductory. 



(New York : Henry Holt and Co., 1886.) 

 This work has been planned by the authors as an 

 "introductory study" to biological science, after di- 

 gesting which the learner may proceed to Huxley and 

 Martin's " Practical Biology," Brooks's " Hand-book of 

 Invertebrate /^oology," or to a second part of the present 

 book, which is promised to be ready some time this 

 year. 



In the first four chapters of the introductory portion, 

 Messrs. Sedgwick and Wilson deal with the generalities 

 of biology — that is, with the nature and properties of 

 protoplasm and the origin and modification of cellular 

 tissues. In the remaining chapters they discuss at full 

 length the two types selected to illustrate the two principal 

 modifications of life. These are, the common brake 

 {Pteris) and the earthworm (Lumbriais). The em- 

 brj'olog}' and physiology of the selected types are as 

 fully dealt with as the pure morphology. At the end 

 of each chapter a scheme of practical work is given, 

 which may in some cases be of much value. 



On p. 123 it is stated that "all the organs of the body are 

 originally developed from the walls of these chambers" — 

 that is, the cliambers of the body-cavity formed by the 

 dissepiments. But it is a well known fact that, as has 

 been previously stated by the authors themselves (p. 152), 

 the nerve-cords and ganglia are developed from the 

 epiblast, or, as Messrs. Sedgwick and Wilson prefer to 

 call it, the " ectoblast." Such being the case, it is obvious 

 that the nerve-cords are not developed from the meso- 

 blastic chambers. 



Another and more serious error will be found on p. 

 143, where the vesicula scminales of the earthworm are 

 described as the testes. It has been conclusively shown 

 by Bloomfield that the large white bodies which fill up the 

 tenth and elev-enth somites of Liimbriciis are really the 

 vesicutce seminalcs. The true testes are very small bodies, 

 only present at certain periods of the year. There are two 

 pairs of them, in the eleventh and twelfth somites. The 

 spermatozoa are not fully matured in the testes, but pass 

 into the vesieiilcs scminales to complete their development. 



Notwithstanding these few errors, .Messrs. Sedgwick 

 and Wilson's introductory essay is well adapted for the 

 use of junior students in biology. Moreover, it is ade- 

 quately illustrated by well-drawn woodcuts, far exceeding 

 in clearness of execution the average of those found in 

 .American text-books. 



LETTERS TO THE EDITOR 

 [Tie Editor Joes not hold himself responsiblt for opinions ex- 

 pressed by his eorrespondents. Neither can he undertake to 

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

 scripts. No notice is taken of anonymous communications. 

 [ The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel facts, ] 



Industrial Studentships 



I .^M directed to request that you will be so good as to allow 

 me, through the medium of your columns, to inform manufac- 

 turers and others eng.iged in industries in which art is more or 

 less concerned, that the Lords of the Committeeof Council on 

 Education have decided to make arrangements for the adinission 

 of a limited number of persons employed in those industries to 

 study in the South Kensington Museum, Library, and Schools, 

 without the payment of any fees, for periods of from two to nine 

 months according to circumstances. 



Detailed rules with regard to these working studentships will 

 be sent on application to the Department. Briefly, the conditions 

 may be stated to be that the designer or workman for whom 

 admission is sought shall show that he h.as sufficient power of 

 drawing and sketching to be able to prolit by the opportunities 

 afforded ; that he is actually engaged in some art industry ; and 

 that the, proprietors of the works in which he is engaged under- 

 take to maintain him while he is studying at .South Kensington. 

 When admitted, the working student will beset, under direction, 

 to study in the Museum and .Art Library from ex.amples relating 

 to the industry in which he is employed, and he will also receive 

 instruction in drawing and designing in the Art .School, suited 

 as far as may be to his special case. 



My Lords have taken this step with a view to render the 

 Museum of more speci 1 and direct use to the country, and they 

 trust that the valuable collection of examples of applied art 

 which has now been brought together may thus be more fully 

 appreciated and taken advantage of by the directors of industry 

 in the country. J. F. D. Donnelly 



Science and Art Department, February 28 



Top-shaped Hailstones 



I.N' connection with the abnormal fall of rain which is taking 

 place this cold Weather in the North-West Provinces of India, 

 and which has clothed the outer ranges of the Himalaya with 

 snow down to the 5000-feet level, I should like to mention a fall 

 of hailstones which occurred on January 21 near Ramnagar, in 

 the Terai. The hailstones were not very remarkable for size, 

 being generally one-third of an inch across, with here and there 

 a larger one half an inch in diameter. Some peculiarities of 

 shape and structure, however, arrested my attention. Nearly 

 every one that was not deformed by collision was top- or pear- 

 shaped. Owing to their rebounding from the ground, it was 

 impossible to see whether the broad or pointed end fell fore- 

 most ; but in every case the broad end was composed of per- 

 fectly hyaline, amorphous ice, whilst the pointed end was banded 

 cr> sswise by alternate layers of clear and white ice. In every 

 case this distinction was perfectly well marked. 



In some few instances I found hailstones of another, but pro- 



