Feb. G, ISJo.] 



KNOWLEDGE « 



111 



Fossil Biachiopodn. The Terel>iat»il:i' (which, from tlicir 

 stupendous antiquity and range in time, have been calleil 

 " the fossil aristocracy ") are the licst-known representatives 

 of this class. The article before us concludes Dr. Pavid- 

 son's Monograph, and consists cf an appendix to its sii|iple- 

 ment, a general summary, and a catnlcgue apd index ef the 

 British species. 



The volume concludes with the seventh part of the mono- 

 graph on the Lias Ammouiti s, by the late Dr. Wright ; 

 the last contribution to the knowledge of a subject on which 

 he was admitttdly one of our greatest authorities, that 

 proceeded from his pen. llis excellent descriptions, at 

 once scientific and perspicuous, are illustrated by some 

 most splendid lithographic plates, by a Mr. Gawan, which 

 are really so marvellously truthful, and look so solid and 

 lifelike (or, in strictness cf diction, natural) as almost to 

 cheat the spectator into the belief that he is regarding the 

 originals. On the value — nay, on the absolute necessity — of 

 these volumes to every student of pala;ontology and collector 

 of fossils In the British Islands, it seems almost superfluous 

 here to insist. So admirably and truthfully are the fossils 

 delineated that are described in the text, as to render such 

 delineations, for all practical purposes, equivalent to their 

 originals for the comparison and identification of specimens. 

 How the Paloeentogi-aphical Society can issue such sump- 

 tuous volumes as this, year after yenr, for its annual sub- 

 scription, we wholly fail to see. Any attemjit to rejieat 

 the experiment on the part of a private publisher would, 

 we fear, result sooner rather than later in an interview 

 ■with a registrar in Portugal street, Lincoln's-inn-Fields. 



SOME BOOKS ON OUR TABLE. 



Maihonatical and Phi/sical Papers. By Sir William 

 Tnosiso.v, LL.D., D.C.L., F.E.S. Vol. II. (Cambridge 

 University Press. 1884.) — Foremost among those who, 

 during the last forty years, have done so much to advance 

 our knowledge of mathematical and experimental physics, 

 stands undoubtedly the name of. Sir William Thomson ; 

 and the second volume of his collected essays, now lying 

 before us, cannot fail to enhance a reputation already ex- 

 tending to every part of the world where the English lan- 

 guage is underctood and scientific information sufficiently 

 diffused to render his wiitings intelligible. The papers in 

 this volume ai'e collected from various scientific periodicals, 

 and range in date from 1854 to 1878. In the very outset 

 the attention of the reader i.s arrested by the famous essay 

 " On the Mechanical Energies of the Solar System," which 

 has been since so fruitful of results in, what it is now the 

 fashion to call, the Physics of the Solar System. This is 

 followed by a " Note on the Possible Density of the 

 Luminiferous Medium and on the Mechanical Value 

 of a Cubic Mile of Sunlight," as is that by an article 

 on " Mechanical Antecedents of Motion, Heat, and 

 Light." Two characteristics will at once strike the 

 careful reader of these essays. The first is the value 

 of our author's quantitative determinations of the forms 

 of energy with which he is dealing. The second the 

 truly scientific spirit in which he frankly withdraws 

 any of his hypotheses which he has found to be untenable 

 since he first advanced them. Nothing is so characteristic 

 of the man of science of the highest class as this. It is the 

 sixth, seventh, eighth, or tenth-rate hanger-on to her skirts 

 who, having once promulgated a hypothesis, adheres to it 

 and continues to proclaim it, after its fallacy has been con- 

 clusively shown. As may be expected, electricity and the 

 theory and practical construction of the electric telegraph 

 occupy a considerable portion of the work, magnetism also 



claiminc no inconsiderable share in it. A short ]>aper on 

 " The Use of Observations of Terrestrial Tempi riiture for 

 the Investigation of Absolute Datis in Geology" will 

 suggest some ])regn:\nt thoughts, too, to the geologist. No 

 one who wishes to trace the steps by which the (lynumical 

 theory of heat has been arrived at, or to undcistaiul the 

 manner in which our existing knowledge of electricity and 

 magnetism has been built up, can allbrd to neglect the 

 perusal of the collected works of Sir William Thomson. 



Practical Pliysics. By it. T. GLAZEiiiiooK, M.A., 

 F.E.S, and W. N. Shaw, M.A. (London: Longmans, 

 Green, it Co. 1884.)— This most recent and excellent 

 addition to the well-known series of "Text-Books of 

 Science" is really, in ed'ect, a rei)roduction of the conti'nts 

 of the SIS. books in which its authors, who are Demons- 

 trators at the Cavendish Lalioratory at Cambridge, were 

 accustomed to write out the practical details of the various 

 experiments performed there. Verbal exjilanations of the 

 principles of physics are, save in certain special ca.ses, 

 almost entirely eschewed, the student being supposed to 

 have familiarised himself with them from the ordinary 

 text-books. Hence its 482 pages are what they profess to 

 be — essentially and eminently practical, and the a])paratU8 

 employed in the various forms of measurement and the 

 methods of using it are described and illustrated in the 

 fullest detail. Slessr.s. Glazebrook and Shaw have pro- 

 duced a book valuable alike to the teacher and the student, 

 and one which supplies a real want in our scientific litera- 

 ture. It should be in the hands of every one engaged in 

 the study of experimental physics in the kingdom. 



Notes on the Origin and Development of Granitic and 

 other allied Varieties of Plutonic Pocks. By J. Reid. 

 (Edinburgh, 1885.) — Having read in the 1853 edition of 

 Lycll's "Principles of Geology," that molten rocks con- 

 tract as they pass into the solid state, it occurred to 

 Mr. Reid that so far from granite contracting as it solidi- 

 fied, it more probably expanded — as does water when 

 passing into ice ; and he asserts that cast iron seems " to 

 expand at the moment of entering into the concrete state " t 

 Why, if this be so, it does not burst its moulds, as ice does 

 a bottle (or even an iron shell) in which the water from 

 which it forms is confined, he does not tell us ; nor why 

 the pattern-maker has to allow as much as J-in. in every 

 foot for shrinkage in making cast-iron pipes. But what i^ 

 of the greatest importance, and what he seems to ignore 

 altogether, is, that natural and artificial fusion give wholly 

 diflerent results. If we fuse rock, we get a stony mass 

 outside as it cools, but inside a slag or glass ; and modern 

 research has shown that granite could only have consoli- 

 dated at a comparatively low temperature. It »iai/ have 

 been pasty, but it never got beyont! that stage. As for 

 the expansion of heated rocks, our author might study 

 Vol. XIII. of the "Transactions of the Royal Society of 

 Edinburgh," p. 3GG. 



Water, Preventible Disease and Filtration. By P. A. 

 Maignex. (London : The Author. 188.5.) — This pamphlet, 

 by the inventor of one of the best-known and most efficient 

 forms of filter we possess, deals with the subject of water 

 impurities generally, and shows but too plainly over what 

 hotbeds of disease from this cause hundreds and thou.sands 

 of us are living. The whole subject of water-purification is 

 dealt with, and simple methods of testing it for impurities 

 given. 



Packard's Shorthand Pepnrtcr and Amanuensis. (New- 

 York : Packard. 1885.) — Stenographic reporting has 

 seemingly taken as great a start on the other side of the 

 Atlantic as it has on this. Here is a new journal devoted 

 to the subject, which apparently comprehends biography, 

 blank verse, instruction, and jokes — not omitting, of course, 



