490 



NATURE 



[September 24, i: 



mention ampere-hours^ and ampere-turns, and Board of 

 Trade units? It would perhaps be going too far to 

 expect him to speak of the drop of potential per ampere 

 in 100 yards of" a cable of nine-seventeens," for he does 

 not aim at displacing the electricians' pocket-books ; but 

 it is to be remembered that of all engineers the electrical 

 engineer is the one who is most inclined to orthodoxy, 

 who most leans upon the mathematician and physicist, 

 who is most likely to use such a book as this ; and if Dr. 

 Everett can stretch a point in his favour, and devote, say, 

 four pages to "electrical engineers' pocket-book" in- 

 formation, it will bind the electrical engineer to ortho- 

 doxy for ever. Why, for example, , should Dr. Everett 

 define the "impedance" of a circuit merely with refer- 

 ence to the circuit when conveying one particular kind 

 of alternating current ? 



This book deserves much more than a short notice, 

 and the time may perhaps come when one of our leaders 

 will write a long critical article on the whole subject of 

 units, pointing out the greit differences in derivation of 

 calorimetric units, for example, and the mere dynamical 

 units employed in mechanics and electricity — an article 

 which will teach the student that, although electric resist- 

 ance has the same dimensions as a velocity, yet this is 

 a very different thing from the statement that it is a 

 velocity ; that, in spite of Paris Congresses and Committees 

 of the British Association, sec-ohm is a scientific name, 

 and quadrant is not. But, over and above all this, the 

 writer of the article must not be, as the present reviewer 

 is, a poor specialist ; he must criticize this book from the 

 point of view of the general physicist. This book contains 

 the results of all the best experimental work of more than 

 a century. It is a book of mnemonics. A single line in 

 the whole book recalls to us those magnificent memoirs 

 of Dr. Andrews which revolutionized our ideas on liquids 

 and gases, and yet that single line is quite enough to the 

 physicist. It is dreadful and yet pleasing to think that 

 all the work of a great man, or perhaps of a generation 

 of great men, may be condensed into a single line of in- 

 formation in such a book as this. Would Dr. Andrews 

 trouble himself very much over this fact if he were alive > 

 or would he console himself with the thought that every 

 physical fact discovered since 1869, and here recorded, 

 was, to some extent, discovered through him, because 

 he had made all physical workers his pupils .? Would he 

 need the consolation that Newton is not once mentioned, 

 and that Sir William Thomson has less space devoted to 

 him than the meanest of his pupils ? Hundreds of years 

 hence, the scientific world will be the better for the ex- 

 perimental work now going on, and it will have forgotten 

 the name of almost every worker. Our determination of 

 something is only right to four significant figures, and so 

 it will never be quoted because a man of next century 

 will have measured it with accuracy to five significant 

 figures. How many of us can be sure that a single line 

 of such a book as this, published a century hence, will be 

 devoted to the record of any of his experimental results 1 

 Is there or is there not a satisfaction in knowing that, 

 one thousand years hence, the names of even Faraday 

 and Maxwell and Thomson will be as little known as 

 ours. The age deserves a Homer, and a memory of 

 thousands of years ; and one book of the epic ought to be 

 a list of all the men mentioned by Dr. Everett, saying 

 NO. I 143, VOL. 44] 



what weapons each of them had brought for the common 

 fight against the powers of darkness. But alas, the new 

 Homer will probably not come into being for another 

 three hundred years, and he will be a blind poet, and he 

 will probably immortalize the wrong people. 



John Perrv. 



OYSTERS. 



Oysters and all about them. Being a Complete History 

 of the Titular Subject, exhaustive on all points of 

 necessary and curious information from the Earliest 

 Writers to those of the Present Time, with numerous 

 Additions, Facts, and Notes. By John R. Philpots 

 (London and Leicester : Richardson and Co., 1891.) 

 The Oyster : a Popular Stanmary of a Scientific Study. 

 By Prof. W. K. Brooks, of the Johns Hopkins Uni- 

 versity. (Baltimore : Johns Hopkins Press. London 

 Agents: Messrs. Wesley, 1891.) 

 TT ISTORIANS of the oyster revel in ambitious titles. 

 -L X <' The Oyster : Where, How, and When to Find, 

 Breed, Cook, and Eat it " suggested a somewhat extensive 

 field for the tiny octavo which Cruikshank illustrated, 

 but yet greater anticipations are raised by the title of Mr, 

 Philpots's contribution to the subject. 



Unfortunately, this promise is not borne out ; not 

 from lack of labour on the writer's part, but from the 

 want of that critical knowledge which can alone make a 

 compilation of this nature valuable. Mr. Philpots has 

 thrown together, with but little arrangement, into two 

 volumes of 1300 pages, scraps from every conceivable 

 source relating to the oyster, and this without any critical 

 treatment whatever : all are oysters that come to his 

 dredge. Since at least as much erroneous information is 

 current about the oyster as about any other well-known 

 animal, and since it appears to exert nearly the same 

 deleterious influence as the horse on the truthfulness of 

 those who deal in it, it will be readily understood that the 

 1300 pages abound with errors and contradictory state- 

 ments, and form a most untrustworthy guide to the 

 complicated subject of which they treat. 



The melancholy side of the situation is that, had the 

 compiler, evidently an enthusiast for his subject, devoted 

 the time and labour expended on the collection of para- 

 graphs from untrustworthy authorities, to qualifying him- 

 self for his task by obtaining a personal and practical 

 acquaintance with the oyster in all its relations of life, 

 he might have produced a less bulky work, but one of 

 permanent value ; as it is, the only passages which we 

 have been able to identify as indicating that Mr. Philpots 

 has seen an oyster or an oyster-bed, are to be found in 

 his account of ten sorts of oysters sent to him by a 

 London dealer, among which, by the way, the real native 

 does not occur (pp. 332-36), and in chapter xix., contain- 

 ing a short account of the Poole fisheries. 



To correct the errors of Mr. Philpots's authorities, and 

 to indicate his omissions, would be to criticize, not one 

 book, but all the readily accessible matter which has been 

 written on oysters for the last half-century ; accessible 

 matter only, for even as a compiler Mr. Philpots has 

 not the requisite quahfications for his task, being 

 seemingly dependent for his information about foreign 

 oysters upon the translations and abstracts which have 



