November 30, 1899] 



NATURE 



lOI 



perature and heat, properties of steam, and work, «S:c., all 

 very thorough and very full of matter for careful thought. 

 In the chapter on the 6<\) diagrams, more advanced 

 theory is taken up ; and, in fact, there are several chapters 

 here that will be above the average student, and will form 

 good reading for the expert ; the facts are marshalled 

 with great skill, and the deductions show that the author 

 is a thorough master of his subject. 



The chapters on valve motion problems and inertia of 

 moving parts are good, and the methods adopted to deal 

 with these very difficult problems are as simple as it is 

 possible for them to be. 



Though only forty-two pages are devoted to gas and 

 oil engines, the author has managed to get in a great 

 amount of most useful information, and to give all that 

 the general student needs. 



The remaining chapters are devoted to certain impor- 

 tant thermodynamic problems and to an inquiry into the 

 properties of superheated steam. 



Most certainly Prof. Ferry has produced a text-book 

 which must be on the shelf of every student of applied 

 thermodynamics, and of every engineer who has to deal 

 with the utilisation of energy. H. B. 



OUR BOOK SHELF. 

 Practical Plane and Solid Geometry for Advanced 

 Students ; including Graphic Statics. By J. Harrison, 

 M.I.M.E., and (1 A. Baxandall. Pp. xii + 558. 

 (Macmillan and Co., 1889.) 

 This book appears to compare very favourably with most 

 English works of its class. The greater part of it deals 

 with practical solid geometry, including the method of 

 indexed plans ; this subject is treated in a much more 

 methodical way than is usually the case, and the 

 authors very properly call attention from time to time to 

 constructions which are of a fundamental character. It 

 is a pity they did not go further, and clearly distinguish 

 throughout the book the worked examples which involve 

 new points of theory from those which merely illustrate 

 general constructions previously given. The directions 

 for making cardboard models ought to be very useful to 

 the student ; and the constructions are explained in such 

 a w.iy as to make the reasons for them intelligible. The 

 section on planegeometry is distinctly above the average ; 

 in particular, there is a very interesting discussion of the 

 description of an ellipse by means of a paper trammel. 

 Of graphical statics only a brief outline is given ; but it 

 is useful enough so far as it goes. There is one error to 

 which attention ought to be drawn : on p. 342 it is stated 

 that the tangent plane to a surface at an anticlastic 

 point cuts the surface in a curve with a double point 

 where there are two inflexions : this is not generally the 

 case, and, in fact, the anchor-ring gives an example of 

 the contrary. Here the section is a bicircular quartic 

 which has a real ordinary node when the tangent plane 

 cuts the ring, and is not parallel to the polar axis. 



Grtindlinien der viaritiinen Meteorolo^e. By W. Koppen. 



Pp. vi 4- 83. (Hamburg : G. W. Hiemeyer, 1899.) 

 This little work serves two purposes ; it is practically a 

 concise elementary meteorology, and a guide for the use 

 of sailors, showing the best routes in the different oceans, 

 with directions for the management of vessels in storms, 

 especially the dangerous West India hurricanes and the 

 typhoons of the China seas. Dr. Koppen has been 

 known for many years as one of the most prominent 

 meteorologists, and having access to the large amount of 

 materials collected by the Deutsche Seewarte, we might 



NO. 1570, VOL. 61] 



expect to find the result of his long experience embodied 

 in a useful and an attractive form. The work meets our 

 expectations in every way ; all details which are un- 

 necessary for the object in view have been carefully ex- 

 cluded, while all technical and nautical expressions are 

 fully explained, so that the work, which is specially 

 written for seamen, may be read with interest and 

 advantage by all who are desirous of obtaining a know- 

 ledge of maritime meteorology. His treatment of the 

 subject includes the general circulation of the atmosphere, 

 as well as the movements of waves, tides and ocean 

 currents, and the value of the treatise is much enhanced 

 by explanatory figures in the text and by separate 

 charts and diagrams. 



Inorganic Chemical Preparations. By Felix Lengfeld. 

 Pp. xviii -f 57. (New York : The Macmillan Company, 

 London : Macmillan and Co., Ltd., 1899.) 

 This is a compact series of instructions for the pre- 

 paration of typical inorganic compounds, the selection of 

 which seems to have been very judiciously made. Re- 

 ferences to original literature are given in connection 

 with each preparation. The author takes care to explain 

 "that the manual is merely a laboratory guide, and that 

 unless the work is carefully supervised, it may become 

 purely mechanical, and the course lose half its value." 

 It is, in fact, a series of recipes, and no attempt is made 

 to explain the innumerable difficulties that will confront 

 the inexperienced worker. This is not said by way of 

 complaint ; on the contrary, it is the incidental and un- 

 expected difficulties of an operation rather than the 

 plain sailing that give the operator occasion to think, 

 and lead to the close association of the teacher with the 

 mind of the learner. 



Mr. Lengfeld purposely refrains from giving a complete 

 list of references to literature, being of opinion that the 

 student should learn to use dictionaries of chemistry. It 

 is doubtful, however, whether the student is able to make 

 a discreet choice from the innumerable references of a 

 dictionary, and we think that the author has rather lost 

 an opportunity in not making his list of references more 

 ample. To those teachers who are introducing more in- 

 organic preparation work into their courses, this book is 

 likely to prove welcome. A. S. 



The Utility of Sulphate of Ammonia in Agriculture. 

 By James Muir, M.R.A.C. Pp. 68. (London : 

 Sulphate of Ammonia Committee, 4 Fenchurch 

 Avenue, E.C., 1899.) 

 This is the essay which won the prize lately offered by 

 the Sulphate of Ammonia Committee. Mr. Muir has 

 carefully compiled his little treatise, and made ajudicious 

 selection of results of field experiments to illustrate the 

 use of sulphate of ammonia, and to compare its results 

 with those obtained from the use of nitrate of soda. 

 Naturally, the results of the Rothamsted experiments are 

 those most largely drawn upon ; Woburn is also quoted 

 from to a considerable extent, and the author consider- 

 ately always gives references to his authorities. The 

 comparisons between the effects of nitrate of soda and 

 sulphate of ammonia are fully and very fairly drawn, and 

 the farmer should find the essay a great help in deciding 

 which of these nitrogenous manures to apply in any par- 

 ticular case. No doubt the farmer, for whom the essay 

 is chiefly written, will turn to the last three pages, which 

 contain a summary of conclusions and comparisons 

 between the two important nitrogenous manures. This 

 summary is in twenty-seven paragraphs, and but few 

 of these lay themselves open to criticism. We can only 

 suggest that the author might have pointed out more 

 clearly in this summary, paragraph 3, that leguminous 

 plants can, under favourable conditions, make use of free 

 nitrogen ; paragraph 7, that nitrogenous manures, and 

 especially ammoniacal manures, do not give their bes 



