324 



NATURE 



[May 12, 192 1 



ridge. The time has come which Darwin foresaw 

 must come. He anticipated that, as our dis- 

 coveries approach the point of human departure 

 from a simian stock, doubts must arise as to 

 whether we are dealing with ape-like men or 

 man-like anthropoids, so great must be their mix- 

 ture of simian and human features. This is the 

 point we have reached in Pithecanthropus and in 

 Eoanthropus, and Prof. Boule has bungled the 

 diagnosis in each case. 



Much as we regret to differ from our distin- 

 guished French colleague, we own to an open 

 liking for his frank verdicts and to a fellow-sym- 

 pathy for some of his human failings. He passes 

 the most severe censure on those who venture to 

 reckon the length of geological periods in years, 

 but presently we find that he himself is a fellow- 

 sinner, and gives 125,000 years as a round figure 

 for his Pleistocene period — which begins with the 

 extinction of Elephas meridionalis — and that 

 about 10,000 years have elapsed since the Ice age 

 ended. Then, again, he will have nothing to do 

 with genealogical trees of man's descent; but 

 anon we find him guessing just as hard as any 

 of us. He admits that the tree that can be most 

 easily "defended" is one which brings man's 

 phylum off from the root-stock of the anthropoid 

 apes ; but all the same he is inclined to go rather 

 deeper for a beginning — to the stock from which 

 anthropoids and Old World monkeys arose — the 

 Darwinian point of departure. Then, again, he 

 expresses the utmost surprise that such a distin- 

 guished man of science as Prof. H. Fairfield 

 Osborn should countenance the reconstruction of 

 fossil forms of man. On an adjoining page we find 

 quite a daring reconstruction of the face of Nean- 

 derthal man, with all the facial muscles dissected 

 out in the most workmanlike manner. In short, 

 we tender the author of this work our sincere 

 homage ; we commend it as a very clear and com- 

 plete compendium of the evidence relating to 

 man's antiquity and origin — with the proviso that 

 the reader must use his own judgment as to the 

 true bearing which the facts here presented have 

 on the problem of man's evolution. 



Arthur Keith. 



British Scientific Instruments. 



Dictionary of British Scientific Instruments. 

 Issued by the British Optical Instrument Manu- 

 facturers' Association. Pp. xii + 335. (London: 

 Constable and Co., Ltd., 192 1.) 215. 



THE British Optical Instrument Manufac- 

 turers' Association, which is one of 

 the industrial associations working in con- 

 nection with the Department of Scientific 

 NO. 2689, VOL. 107] 



and Industrial Research, has just issued this 

 very useful dictionary. The main part of the 

 work consists of a list of British instruments 

 arranged alphabetically, with a brief description 

 of each and an indication as to the firm or firms 

 which supply it. Illustrations of a large number 

 of the more important instruments are also in- 

 cluded. Some of these are shown in position at 

 the National Physical Laboratory. The utility of 

 the book is obvious ; it serves as a dictionary to 

 the inquirer who wishes to know something about 

 an instrument which he hears mentioned in con- 

 versation or reads of in a book; it is also a trade 

 handbook, giving the would-be purchaser at a 

 glance information as to where an instrument he 

 desires to acquire can be obtained. This, however, 

 is not all; the volume illustrates in a remarkable 

 way the activities of the trade, the range of instru- 

 ments of British manufacture, and the debt men 

 of science owe to the instrument maker. The 

 work has been well carried out, the list is very 

 complete, and cross-references are numerous ; the 

 definitions or explanations are clear and concise. 

 Thus : — 



" Galvanometer.- — An instrument for measuring 

 electric currents usually by the deflexion of a 

 magnetic needle in the magnetic field created by 

 an electric current, or by the deflexion of a moving 

 coil, carrying the current, in the field of a fixed 

 magnet. There are thus two main types : the 

 moving magnet and the moving coil galvano- 

 meter." 



Or again : — 



"Hydrometer. — An instrument for determining 

 the specific gravity of liquids. Attributed to 

 Archimedes, but not much used until it was re- 

 invented by Robert Boyle. It usually takes the 

 form of a narrow sealed instrument of cylin- 

 drical section, and consists of three parts — the 

 counterpoise at the bottom ; the bulb containing 

 air ; and the stem with the scale at the top. Made 

 of glass or gilt brass. In the latter case the hydro- 

 meter is usually provided with weights which are 

 slipped over the stem and alter the buoyancy of 

 the instrument so as to adapt it to liquids of vari- 

 ous specific gravities." 



Useful illustrations of various patterns of gal- 

 vanometer are given ; it is a mistake, however, ta 

 spell Sir Wm. Thomson's name with a "p," and 

 the astatic mirror galvanometer figured is one of 

 his. 



But there is more in the book than this dic- 

 tionary. Meteorology, navigation, and astronomy 

 have long been subjects of investigation, and many 

 of the instruments described have been devised in 

 order to facilitate the study of the weather and the 

 stars, or to assist the navigator on the trackless 

 waters. Hence there have been included very 



