NA 7 URE 



[Nov. 27, ii 



sition of vectors were assumed outright. The author 

 is probably now the only surviving writer on dynamics 

 who persists in muddling up force and acceleration by 

 calling acceleration (a purely kinematical quantity in 

 itself) an " accelerating force," and he adds to the muddle 

 by writing v = ft where all modern writers would put 

 v = at. What the student is to understand by "a force 

 capable of generating in one second a velocity represented 

 by D E" (p. 27) is difficult to see, when the mass on which 

 the force is to act is nowhere stated, and when it is not 

 even stated or hinted that there is any mass at all 

 to be acted on. On p. 41 the author states that 

 " in this country the ounce avoirdupois is so taken 

 that one thousand of them will just balance a cubic 

 foot of distilled water." This is not so, at least in 

 this country, for the mass of the ounce depends on the 

 standard pound, and this was established without any 

 reference to a standard volume of water. The definition 

 is wrong ; the fact it states is a mere coincidence ; and 

 the coincidence itself is not exact : a cubic foot of water 

 does not weigh 1000 ounces. On the same page the 

 author tells the reader to ascertain with respect to a 

 certain mass the velocity which " a given pressure or 

 impulse " will impress upon it ; " the mass being inversely 

 proportional to this velocity." The confusion between 

 pressure, which cannot be expressed except in terms of 

 force divided by area, and impulse, which is expressed as 

 force multiplied by time, is truly amazing. Is time the 

 reciprocal of an area ? Again, on page 42 the author is 

 speaking of a certain force capable of sustaining a certain 

 weight for one second of time, and he says "it would 

 require twice as powerful a force to enable it to resist the 

 action of gravity for two seconds, three times for three, 

 and so on." This is news indeed. In the section on 

 hydrostatics, no sooner has the student learned that a 

 pressure of one pound per square inch is equal to 100 lbs. 

 per 100 square inches, than he comes to such a statement 

 as the following (p. 52): "The pressure therefore exerted 

 by a mass of fluid upon the bottom of a vessel containing 

 it is proportional to the area of the base," &c. Here the 

 author jumps, without one word of warning to the student 

 as to his change in the use of words, from using the word 

 pressure in its proper sense of so many pounds-per-square- 

 i/ic/i, to using the word in the sense of so many pounds, in 

 which case it is no longer a ' pressure " but a "force." 

 It may be said perhaps that these things are but slips of 

 the pen. Perhaps they are ; but in a teacher who 

 undertakes to write a text-book of " first principles" slips 

 of such a kind are unpardonable. No such confusion of 

 thought would be tolerated in the pupil who had read 

 WormelFs " Dynamics," or Lodge's " Mechanics," or 

 Maxwell's " Matter and Motion," or Thomson and Tait's 

 lesser volume. If Mr. Lynn does not intend his text -book 

 to be cast aside as worse than useless, he must at once 

 correct blundering modes of thought that can only 

 mislead the student. 



Elhnents de Mecanigue, avecde nombrem Exercices. Par 

 F. I. C. Pp. 282. (Paris : Poussielgue Freres.) 



This is the concluding volume of a series of elementary 

 class-books on pure and applied mathematics issued by 

 l'lnstitut des Freres Ecoles chretienncs, a French Society 

 which showed in the Technical Schools at the recent 

 Health Exhibition a noteworthy collection of specimens 

 of woik done in their schools, along with the educational 

 apparatus used therein. 



The character of the book before us harmonises with 

 the evident sympathy of the Society with the manufac- 

 turing industries of the districts in which their schools 

 are situated. We are furnished with an introduction to 

 applied as well as to theoretical mechanics. There are 

 good diagrams and descriptions of weighing-machines, 

 cranes, and other lifting-tackle in the section on statics ; 

 the longest chapter in kinematics is concerned with the 



simpler forms of mechanism ; and in dynamics there is 

 a full discussion of the principle of work and its applica- 

 tion to mechanics. 



The text is clear, as far as it goes ; but we think the 

 general exposition of the theory too concise, many im- 

 portant points being relegated to the exercises at the end 

 of each chapter. 



There is a good collection of problems filling the last 

 fifty pages of the book, but no examples are worked out 

 in the text, and there are no results given to any of the 

 exercises. Clearly, pupils using the book would require 

 a good teacher at hand, who could devote ample time to 

 the subject. 



We should wish to see a book like this with a few select 

 students, but, having regard to general class instruction, 

 we do not think the mode of treatment a happy one. 

 We feel called upon, however, to give a cordial recog- 

 nition to the expansion in the direction of technical 

 instruction, to the liberal supply of good diagrams, and to 

 much freshness of treatment, both in text and examples, 

 in the work before us. A. R. W. 



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, rej:ctcd manuscripts. 

 No notice is taken of anonymous communications. 

 \71ie Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel fxcts.~\ 



Chemical Research in Great Britain 



At the anniversary meeting of the Chemical Society held 

 March 31, 1S84, the President read an address to the Fellows, 

 which contains a series of remarks upon the prosecution of 

 original research in England requiring some notice, particularly 

 as a separate issue of the address lias heen circulated by the 

 author. Attention is directed to the fact that we have an 

 increased number of laboratories in Great Britain 1 and greater 

 facilities for the prosecution of research through the aid of the 

 Government grant and the Chemical Society's fund. Notwith- 

 standing this the startling and anomalous fact is to be observed 

 lliat the number of papers read before the Society is declining 

 year by year. 



After speaking in terms of praise of the degree of Doctor of 

 Philosophy of Germany, which necessitates die prosecution of 

 some original investigation, there follow some remarks which 

 read like a serious reflection on a number of professors who have 

 won distinction through unreinunerative devotion to scientific 

 teaching and research. 



"The past neglect of research will, it is to be feared, have a 

 more lasting influence on the progress of chemistry in this 

 country than may appear at first sight, and in this way. Those 

 who have been students in laboratories where the importance of 

 this kind of work is not recognised, advance in their positions, 

 becoming assistant demonstrators, &c. , and eventually professors, 

 and as they have not learnt to practically realise the value of 

 research by being in the habit of conducting it themselves, or of 

 seeing others do so, when they become professors they will 

 naturally not encourage students to undertake it in their labora- 

 tories, and it is to be feared that we are already suffering in this 

 way, and that this is one of the causes why the new laboratories 

 which have been opened are doing so little to add to our store of 

 fresh knowledge." 



It will be questioned whether such a statement can be justified 

 when it is mentioned that there happens to be lying on the table 

 before the wrier four reprints of papers recently received from 

 the respective Professors of Chemistry in four of the new col- 

 leges ; three of these memoirs are published in the Philosophical 

 Transactions of the Royal Society, while a fifth occupant of one 

 of the newly create.! chairs not long since received the Longstafl 

 Medal. The whole subject seems scarcely to have been so 

 well considered as to lead to a just appreciation of the cir- 



' The term used is the United Kingdom, which includes Ireland. There 

 has been no increase in the number of laboratories in Ireland, and only an 

 increase of one in Scotland. 



