September 22, 1904] 



NA TURE 



505 



branch attack on the theory of genetic evolution are 

 as brightly and easily written as the rest ; their matter, 

 however, will be entirely unconvincing to those who 

 know the facts. The author has got up his case as 

 a clever advocate might get up his address to a jury ; 

 but the cross-examination of witnesses would put a 

 very different complexion on the whole business. 

 Father Gerard seeks to prove too much. His plea 

 amounts to an allegation in the name of science that 

 a science of life is non-existent. F. A. D. 



Occurrence of Aluminium in Vegetable Products, <5fC. 



Bv C. F. Langworthv, Ph.D., and P. T. Austen, 



Ph.D. Pp. v+168. (New York: John Wiley and 



Sons; London: Chapman and Hall, Ltd., 1904.) 



Price 8s. 6d. net. 

 .■\kter a careful perusal of this book we have been 

 unable to arrive at any conclusion as to why it was 

 written. The authors presumably had some reason for 

 compiling a bibliography of the analytical work done 

 on aluminium and its occurrence in plants, animals, 

 and waters, but they give no idea as to their object 

 in their preface. 



The book, as already stated, consists of a compilation 

 of work dealing with the occurrence of aluminium in 

 vegetable products, animal products, and in natural 

 waters. In the preface it is stated that " no attempt 

 has been made to comment on the value of individual 

 analyses cited." Now by omitting to do this the book 

 loses any value it might have had, because the refer- 

 ences given are so extremely scanty. One or two 

 examples taken at random will give an idea of the style 

 of compilation, e.g. on p. 9 we find : — 



" Coppola, M. (Gaz. Chim. Ital., 10, p. 9 : jour. 

 Chem. Soc. London, 37 (1880), p. 3S2), found 11. 16 

 per cent, ash in Stereocaulon vesuvianum. Of this 

 I- 13 per cent, was ALO3." 



.\gain, on p. 73 :— 



" Finckh, C. {Neue. Jahrb. Pharm., 34, p. 13; Chem. 

 Centbl., 1870, p. 615; Jahresb. Chem. Naumann, 1870, 

 p. 1382), notes traces of aluminium in Ochsenhausen 

 mineral water from Bieberach, German}-. " 



Both these illuminating passages are taken from the 

 middle of the respective pages. On p. 73 there are 

 seven and a half such references, and on p. 9 eight. 



The contents of the book are not arranged in any 

 order, except that the authors' names are placed 

 alphabetically. Consequently, if one looks up tea in 

 the index in order to ascertain whether it contains 

 aluminium, one is referred to p. 32 ; after a lot of 

 hunting we find tea under the name of Schriddl, P. 

 (Arch. Pharm., 1873, p. 375). . . . Again, if we wish 

 to know the aluminium content of mushrooms, we are 

 referred to p. 15, where we can find nothing about 

 mushrooms, unless Boletus edulis is a mushroom; 

 or is poke-weed the American name for mushroom? 



In desperation we look up primrose, and are re- 

 ferred to p. 42, and at last we are satisfied; the root 

 of the primrose contains 1-617 P^r cent., and the flower 

 heads 1-145 P*^"" cent., of aluminium oxide. 



Works of compilation are often of great value, but 

 they can only be of value when the contents are 

 systematically arranged. To arrange a dictionary 

 such as this according to the names of the authors is 

 absurd. The pitiable thing about the whole matter is 

 that the authors must have wasted a great deal of 

 valuable time, because a compilation of this kind is 

 extremely tiresome and laborious. 



Practical Chemistry. By P. A. E. Richards, F.I.C. 



Pp. viii + 136. (London : Bailliere, Tindall and Cox, 



1904.) Price 3.?. net. 

 So long as examinations in practical cheniislrv of the 

 test-tube order are encouraged bv examining bodies, 



NO. 1821, VOL. 70] 



there will be a steady consumption of chemical cram 

 books. I he peculiarities of such books are that the 

 student IS never allowed to step outside the limits of 

 his syllabus without due warning, and his weary brain 

 IS not perplexed with explanations. Like the cattle 

 in the large tinned meat factories, he is driven along 

 a narrow gangway in which he cannot turn round 

 until he IS delivered into the hands of the slauo-hterer 



Fortunately the more intelligent examining bodies 

 are beginning to realise that the analvsis of simple salts 

 does not furnish scientific pabulum of a verv nourish- 

 ing kind; so preparations of a few inorganic com- 

 pounds and a little volumetric analysis have been added 

 to the syllabus. 



The present volume has been prepared to meet the 

 special requirements of the syllabuses of the conjoint 

 board and the preliminary scientific examination of 

 the London University. 



It is only necessary to state that the author has 

 completed his task in a thoroughlv business-like 

 manner. A student who worked through the book 

 conscientiously might with confidence defv the conjoint 

 examiner to do his worst. ' j. g q 



Calculations used in Canc-Sugar Factories Bv 



I'T'"f,P- ^°''*^' ^-S- PP- viii + 74- (New York': 

 John Wiley and Sons; London : Chapman and Hal! 

 Ltd., 1904-) Price 6s. 6d. net. 

 This collection of tables was primarilv made for the 

 use of the sugar chemists of Louisiana, 'but it is equallv 

 applicable to the operations of every manufacturer of 

 cane-sugar. The work may be recommended to all 

 who seek to use the laboratory as a control of the 

 working of the sugar-house. In every well regulated 

 factory the manager is dependent u^n the chemist 

 for information as to the amount of sucrose in the raw- 

 juice, the yield of sugar, the losses in manufacture, and 

 whether or not all the available sugar is being ex- 

 tracted from the cane, and the eflficiencv and value of 

 the laboratory largely depend upon the rapidity and 

 accuracy with which this information can be furnished. 

 The work is thoroughly practical, and is evidently the 

 outcome of many years' experience of sugar testing. 



LETTERS TO THE EDITOR. 



\The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

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

 manuscripts intended for this or any other pari of Nature. 

 No notice is taken of anonymous communications.] 



Colours due to Intermittent Illumination. 



Mr. C. T. Whitmell (Nature, September i, p. 424) 

 describes a method of producing coloured patches by means- 

 of a rotating disc, furnished with a ring of holes. It will 

 be found that the phenomenon can also be produced bv inter- 

 mittent reflection. In the year 1881 I described in Nature 

 (vol. xxiv. p. 140) a method whereby colour patches of great 

 brilliancy, due to intermittent illumination, were easily pro- 

 duced by viewing sun-light reflected from the polished spokes 

 of a cycle wheel. The relationship between the colour given 

 and the velocity of rotation was clearly marked, and the 

 effects can be easily reproduced by means of the simple 

 apparatus described. In these experiments, a counter was 

 attached to the axle of the rotating wheel, so that the rate 

 of rotation could be accurately determined at the time of 

 obser%'ation. The rotation of the cycle wheel was main- 

 tained by means of a motor the speed of which could be 

 easily varied. In connection with the phenomenon of the 

 change of colour due to intermittent illumination, several 

 papers of much interest have been published since the year 

 1882 by Dr. G. Burch, F.R.S. F. J. Jervis-Smith. 



Trinity College, Oxford, September 13. 



