August i8, 1903] 



NA TURE 



365 



the various forms of fish pass are considered — the pool 

 fishway, the oblique pass, queen's gap, and the 

 various forms of fish ladders. The various forms are 

 described, but are quite insufficiently criticised. The 

 oblique groove, " Schrjigpasse " (under which, by the 

 way, is included the queen's gap pass, " W'ehrein- 

 schnitt ") is dealt with at some length, although it, i.e. 

 the oblique groove, was years ago considered utterly 

 useless in Britain, where it was chiefly tried. 



The information upon fish ladders is arranged under 

 headings " Fischtreppen mit Stegen," " Fischtreppen 

 init .Sperren u. Einschnitten," and " Lachstreppen mit 

 Sperren u. Schlupfoffnungcn," no distinction being 

 drawn between step fishways and inclined lishways, 

 although, in Britain and America at any rate, the latter 

 form h.'is been considered vastly superior to the 

 fcinncr 



St'eing that the author in his preface undertakes the 

 consideration of foreign fishways as well as of German 

 ones, we should have expected to see more fish ladders 

 described and discussed, especially those of this 

 country and America, where this branch of engineering 

 has had plenty of scope. The " Smith's Ladder " at 

 the lower falls on the Ballysadare River is described 

 and figured, but no mention is made of the ladder at 

 the C"ollooney Falls on the same river, which is a 

 combination of Call's and Smith's inventions. The 

 first Smith's pass, and one of the most successful in 

 .Scotland — that at Deanstone, on the Teith — surely de- 

 served mention, as did the inventor. The " queen's 

 gap " at Poolquay Weir, on the Severn, is described 

 in detail, although the weir was washed away in 

 ]88i, and has never been rebuilt. 



Part iii. is devoted to fish-ponds. There is only one 

 reference to an English fish farm, and none of the 

 numerous .American hatcheries, where pond construc- 

 tion has been carefully studied, are mentioned. 



.Much of this part of the book is of less value from 

 the British fish culturist's or engineer's point of view, 

 because in Germany coarse fish, such as the carp, are 

 a staple food, and are reared in large numbers, whereas 

 most of our fish culture is concerned viith the 

 Salmonidae. As the author says : — 



" Dcr Karpfen ist derjenige Fisch, der sich am 

 besten fiir die Teichwirtschaft eignet. Er ist ein 

 Edelfisch, leicht zu ziehen und schnellwiichsig, so dass 

 er gute Ertrage liefert," 



and this section of the book is written very much from 

 this point of view. 



.Much of the information as to the construction of 

 ponds and their inlets and outflows is, of course, 

 ancient, and can be found in such books as the 

 " History of Howietoun," by the late Sir R. Gibson- 

 Maitland. 



The book is doubtless a useful exposition of some of 

 the existing fish passes and ponds, but in such a work 

 we should have expected to find fuller criticisms and 

 summaries, for instance, as to the value of one form 

 of pass compared with another. 



On the whole, we think a more useful book could 

 be written from a British engineer's point of view. 

 Frank Balkour Brow.ne. 

 NO. 18 16, VOL. 70] 



OVK BOOK SHELF. 

 Photographic Chemicals and How to Make Them. 



By W. Taylor. Pp. 107. (London : Ililfe and Sons, 



Limited.) Price is. 

 This small volume of a hundred pages consists of 

 explanatory remarks on various chemical operations, 

 such as filtering, weighing, boiling, and so on, and 

 concise instructions for the preparation of twenty-one 

 substances that are in common use by photographers. 

 The author considers that " the processes may form 

 a pleasant variation upon ordinary photographic 

 methods." He adds that "it must not be supposed 

 that there will be a saving of cost," but " the pleasure 

 and amusement afforded by the manipulations, to say 

 nothing of their value educationally, if followed out with 

 due care, should do far more than compensate for the 

 trifling increase in expense." The instructions given 

 are clear and correct, and are illustrated by several 

 good figures of really practical apparatus, but, as is 

 often the case in such volumes, the style is uneven. 

 If the book is intended for those who will profit by 

 being told how to test with litmus paper and how to 

 bend a glass tube, and need to have figures to show 

 what kind of things a pestle and mortar, an evaporat- 

 ing dish and a pair of tongs are, then the descriptions 

 of processes are far too lacking in detail. They are 

 more of the character of instructions that might be 

 given to a student of chemistry who has had experi- 

 ence in a well appointed laboratory. We very much 

 doubt whether the author or anyone else has boiled 

 away sulphuric acid " in an empty grate " — of ar> 

 ordinary room, presumably. The open air is sug- 

 gested as an alternative place for the performance of 

 this and many other operations which would very 

 speedily render it impossible to live in any room where 

 they were going on. The risk of accidents or desir- 

 able precautions might have been set forth a little 

 more prominently in case the volume should fall into 

 the hands of those who know nothing of chemistry. 

 However, there are many young people who have 

 " done " a little chemistry at school, and these will no 

 doubt find it useful. It may be noted that the method 

 described for preparing anhydrous sodium acetate is 

 not efficient ; it is necessary to fuse the dried salt. 



Dictionnaire des Engrais et des Produits chimiques 

 agricoles. By E. S. Bellenoux. Pp. x+158. 

 (Paris : Schleicher Freres et Cie., 1904.) 

 This is meant to be a handy book of reference for the 

 farmer and the agricultural student, in which any 

 material used in agriculture may be looked up and 

 information obtained as to its nature, use, adulteration 

 and the like. The arrangement is alphabetical under 

 such heads as "analysis of the soil," "ash," 

 "nitrogen," "purchase of manures"; the treatment 

 is popular, and though results of experiments are 

 occasionally given, there are no references. The 

 scheme of the book causes a good deal of overlapping, 

 and we doubt if the same end of easy reference would 

 not be better attained by a good index to an ordinary 

 book covering the same ground. The .information 

 provided is not very well selected nor always correct; 

 for example, we read, " le sulfate d'ainmoniaque a, 

 au contraire, la propriete de remonter des profondeurs 

 du sol oil I'eau peut I'avoir entraine et de revenir k 

 la surface: c'est un sel grimpant, ainsi qu'on I'a 

 d^>nomm^, et c'est cette proprit^tt;' sptfciale qui le fait 

 employer avant I'hiver afin que les pluies le fassent 

 penetrer jusqu'aux racines. Si on I'emploie au prin- 

 temps, il faut I'enfouir par un labour et ne jamais le 

 r^pandre en couverture. . . . L'azote du sulfate 

 d'ammoniaque est directement assimilable par les 

 plantes. " 



