Nov. 22, 1883' 



NA TURE 



lb 



In one respect this task has presented difficulties of a 

 peculiar nature, due to the fact that our country has taken 

 a leading part in developing the principles of energy — 

 this science has in fact grown here, and the terminology 

 has grown with it. At the present moment there is no 

 man of science who speaks of the forces when he means 

 the energies of nature, but there is a lagging behind in 

 this respect amongst the body of the people, to whom the 

 word force is a familiar one, and the word energy, in a 

 scientific sense, very much the reverse. Accordingly one 

 of the first duties of the author has been to define the 

 exact relations between force and energy in a way suit- 

 able to his audience — a task which he has successfully 

 achieved. 



While in respect of importance the science of energy 

 holds a paramount place, it is also a subject which lends 

 itself admirably to the mode of treatment adopted by the 

 author of this volume. Probably no subject is more diffi- 

 cult of conception on general principles merely,and without 

 reference to the actualities of life. The philosopher in 

 his study may have but a vague conception of these 

 general laws, and his assent to the definition of work may 

 be purely intellectual. Perhaps he may never have 

 V. itnessed a well marked case of the transmutation of 

 energy, nor may he have the consciousness that he 

 himself is frequently the subject of such transmutations. 

 The artisan is, however, in a totally different position. 

 After a day's hard toil he is well able to realise in a very 

 vivid manner the meaning of the word iL'ork. To spend 

 his personal physical energy, and to recruit it by food, 

 are operations in which he is constantly and consciously 

 engaged. Hence it follows that a theory which borrows 

 all these facts as illustrations of its truth appeals to the 

 artisan in a much more emphatic way than it does to the 

 mere student of science. To use the scientific termino- 

 logy, the latter may have more kinetic intellectuality than 

 the former, but the artisan is in 3. position of adininiage 

 which enables him to grasp the truths of the science. A 

 book, therefore, which, hke the present, abounds in good 

 illustrations and in clear and simple statements, carrying 

 practical applications, is one peculiarly fitted to a class 

 better qualified by education and experience to perceive 

 the concrete than to appreciate abstract general prin- 

 ciples. B. S. 



Journal of the Royal Agricultural Society. Second Series, 

 Part II. Vol. XIX. October, 1883. Price 6s. (London: 

 John Murray.) 

 The current number o{ tht fournal of the Royal Agricul- 

 tural Society has just reached us. It fully maintains the 

 reputation so justly earned by previous numbers, and 

 contains papers on many topics of present interest to 

 agriculturists. Among the principal of these may be 

 mentioned " The Progress of Fruit-Farming," by Mr. 

 Whitehead, of Barming House, Kent, himself largely in- 

 terested in this business. The continued reports upon 

 Prize Farms are worthy of attention as showing what is 

 being done on the best farms in various districts. A re- 

 port on sheep-feeding experiments conducted at Woburn 

 by Dr. Voelcker in his capacity of chemist to the Society, 

 and a report on wheat mil iew, by Mr. W. C. Little, of 

 Stag's Holi, form the chief attractions to practical farmers. 

 Among tli.e more purely scientific or speculative contents 

 maybe mentioned a con • ri ^ution from Rothamsted, by 

 Sir John Lawes and hi^ able coadjutor, Dr. Gilbert, upon 

 the composition of drainage water collected at Rotham- 

 sted, ana a valuable paper upon nitrogen as nitric acid in 

 the soils and subsoils of certain fields on the same estate. 

 The rem.Mnder of the vo'ume is chiefly occupied with 

 useful official matter, such as the Weather Report ; the 

 Botanical Report, by Mr. Carruthers ; and Reports on 

 Live Stock, Implements, &c., exhibited at York. A 

 touching tribute is paid to the memory of a late president 

 of the Society, the late Lord Vernon, by Mr. Wells, him- 



self an ex-president. Perhaps the most striking and in- 

 structive paper is that by Mr. Thomas Bell upon the 

 Yorkshire Prize Competition, containing a full report of 

 the Tuycrs Wood and East Park Farms, occupied by 

 Mr. Turnbull. In these days, when dairying is justly 

 attractmg very special attention, it is highly interesting 

 to receive sound information as to the methods used on 

 thoroughly well-managed farms. A daily record of the 

 milk yielded by each cow in a dairy containing 100 

 animals in milk is in itself highly useful, and worthy of 

 imitation. It is impossible in a short notice like the 

 present to open up the various topics dealt with. It has 

 ever been the wise policy of the " Royal Agriculturist " to 

 fill its pages with contributions from specialists upon 

 their own specialities. There is no padding or super- 

 fluous discursiveness, and sometimes to the uninitiated 

 there may appear to be a want of that introductory and 

 explanatory matter which entices on the general reader. 

 As a record of agricultural research and progress, the 

 journal holds a high position, which the number just 

 issued fully maintains. J. W. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himscif responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond loith the writers of, rejected mantiscripts. 

 No notice is talzen of anonymous communications. 



[The Editor urgently requests correspondents to keep their letters 

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

 that it is impossible othenvise to insure the appearance even 

 of communications containing interesting and novel facts.l 



On Chepstow Railway Bridge, with General Remarks 

 suggested by that Structure 



In a letter to Nature of some months past, suggested by a 

 special subject of engineering, I pointed out the necessity 

 of clearly understanding the effects of endwise pressure on 

 metallic columns, in respect of its tendency to cause springing or 

 huckling of the columns. I remarked that there is a total want 

 of experiments on the subject (Mr. Hodgkinson's observations, 

 made on a very small scale, being excepted), and I gave some 

 details of a theory by which the effective arrangement of such 

 experiments might perhaps be facilitated. I have lately ob- 

 served in an engineering work a failure of a different class 

 arising from endwise pressure, of a kind which I had not antici- 

 pated, and which appears to be perhaps more dangerous than 

 even the buckling to which I had called attention. 



In the neighbourhood of Chepstow, the River Wye is crossed 

 by a railway bridge of a single span. The four corners of the 

 bridge are supported by iron tubular vertical, columns of con- 

 siderable length. One of these columns (on the Monmouthshire 

 side of the river, and on the lower side of the bridge as regards 

 the course of the river) is split, with several important longitu- 

 dinal fissures. To avert the present destruction of the bridge, 

 strong iron hoops have been placed surrounding this tube, drawn 

 tight by screws and nuts, exhibiting a somewhat imsightly 

 appearance. 



For clear understanding of this state, the reader may figure to 

 himself a cask or barrel, set on its end, and loaded on the top 

 till its staves burst outwards ; then he must conceive a hoop to 

 be placed round the bjdy of the cask, and drawn till the edges 

 of the staves are wholly or nearly in contact. 



I do not doubt that this column is now safe. But there are 

 other columns supporting the bridge which are exposed to the 

 same dangers : the bridge is heavy, the loads from the Taff and 

 the Tawe are not light, and the jar of ponderous locomotives 

 may try every original weak point or may create new ones ; and 

 I think it would be well provisionally to encircle the other sup 

 porting columns in the same way as the one which has faded 



