December 22, 1904] 



NA rURE 



173 



second gives the simple theory of the deflection of 

 kathode rays, for the benefit of those not entirely 

 unacquainted with mathematics; while the third 

 describes the chemical processes involved in the 

 extraction of the radio-active products from pitchblende 

 residues. 



The general arrangement is good, but there appears 

 to be more than the usual allowance of uncorrected 

 errors in spelling and composition. We hope that a 

 second edition will give the author an opportunity of 

 correcting these. 



On the whole the book may be thoroughly recom- 

 mended to the general reader as an accurate and 

 attractive account of the latest aspect of scientific 

 thought on the structure of matter ; whilst the 

 specialist will find numerous passages which are 

 suggestive and stimulating. 



O. W. Richardson. 



LABORATORY EXERCISES IN BREWING. 

 Laboratory Studies for Brewing Students. By A. J. 

 Brown, M.Sc, &c. Pp. -wiii-l- 193. (London: 

 Ivongmans, Green and Co.) Price ys. 6d. net. 



THE brewing school at Birmingham is fortunate 

 in possessing Prof. Brown as its head, and we 

 hail the appearance of his book as extending its 

 advantages to students of brewing generally. 



These Laboratory Studies describe a systematic series 

 of experiments illustrating the scientific principles 

 underlying brewing. The author is careful to point 

 out that he does not aim at dispensing with a teacher. 

 Assuming a knowledge of chemical manipulation, he 

 gives the detail necessary for the successful perform- 

 ance of each experiment, and draws the appropriate 

 conclusion. He frequently connects the conclusions 

 with others from allied experiments, and even to some 

 extent with brewing practice, but at each step more 

 and more scope is left for the teacher to discuss the 

 bearing of the results on one another and on large scale 

 work. If the author published his own lectures we 

 should doubtless find them an exceedingly valuable 

 complement to the work before us. 



The book is divided into four sections : — (i) barley 

 and malting ; (2) principles of the mashing process ; 

 (3) fermentation ; (4) hops. These sections are further 

 subdivided into parts and paragraphs, the latter corre- 

 sponding to each experiment. 



The first section follows the changes in outward 

 appearance from the flowering stage to the ripe barley 

 corn, and thence passes on to the anatomy of the corn 

 and to its conversion into malt. 



Under the heading dealing with the varieties, we 

 find one of the inany instances of the way in which 

 the author equips his men for taking their part in the 

 controversies of present day brewing but avoids all 

 dogmatising on points still sub judice. The experi- 

 ments are planned so that the student will know 

 all the characteristics of, e.g., Chevallier (we 

 adopt Mr. Beaven's spelling of the rev. gentleman's 

 name) and Goldthorpe, but he is left with an 

 NO. 1834, VOL. 7 l] 



open mind as to the vexed question of their rival 

 merits. 



Dealing with the technical examination of malt 

 (and, indeed, also of barley and hops), we are glad to 

 find due recognition given to expert knowledge — the 

 student being specially commended to the teacher foi 

 instruction in it. For we are apt nowadays to under- 

 rate the knowledge accumulated by the practical man 

 — what corresponds to the " farmer's eye " is still of 

 immense value to the brewer. 



Section i., part v., devoted to the chemical examin- 

 ation of malt, is as good as any in the book. Heron's 

 method of determining the yield of extract is very 

 fairly criticised, and we leave the subject with a full 

 appreciation of its value and difficulties. The foot- 

 note of p. 46, that " a thoroughly satisfactory malt 

 mill is yet to be introduced," should appeal to all 

 interested in brewing. 



Section ii., the principles of the mashing process, 

 deals with the changes which take place when malt 

 and water are brought together at various tempera- 

 tures and sketches the analysis of wort as far as the 

 carbohydrates (much the largest constituents) are con- 

 cerned. We were sorry that, in giving the experiment 

 showing that the influence of heat in restricting starch 

 transformation is due to modification of the diastase, no 

 reference is given to Kjeldahl's " Recherches sur 

 les ferments producteurs de sucre " [Risumi du 

 Compte rendu des Travaux du Laboratoire de Carls- 

 berg, i, 109), but this is perhaps on account of its 

 being in a foreign language and so unsuitable for 

 students. 



Section iii. is devoted to fermentation, but, as there 

 are already books, chiefly by the Hansen school, deal- 

 ing with this important subject, this section is a good 

 deal curtailed. We are, however, glad to see (even 

 if they are in small print) experiments on the author's 

 important discovery that the maximum number to 

 which yeast cells multiply in a nutritive solution de- 

 pends, not on the number of cells with which the solu- 

 tion is seeded, but on the volume of the solution, 

 granted, of course, a sufficiency of food. 



Section iv., on hops, concludes the volume. We 

 wish an experiment had been included to show the 

 restrictive action of hops on the acid-forming bacteria, 

 but such an experiment is not a very easy one for 

 students. 



It will have been noticed that the book adheres to 

 the usual plan of beginning with barley and ending 

 with beer. This seems inconsistent with the custom 

 of passing from the well known to the less well known, 

 and we should like to see tried the opposite plan of 

 starting with beer and tracing it back into its con- 

 stituents. 



In training men for technical work the course should 

 be; first, a general grounding in science; secondly, 

 practical experience of the art in question ; thirdly, a 

 study of the scientific principles involved. If this be 

 so the work before us should not only be of service 

 to students but also to those brewers who desire to 

 look into the experiments on which the principles of 

 their art are founded. 



