128 



NA TURE 



[December 3, 1908 



vellow colour, which gives it the distant resemblance 

 to a hornet from which it derives its name, but this 

 is confined to its colour, for the long, tapering Asilus 

 differs altogether in shape from a hornet. 



The species of the next family, Bombyliidae, are 

 stout and hair\', and those of the typical genus Bom- 

 bvlius have a remarkable resemblance to small Bombi 

 (humble-bees), from which, however, the two wings 

 and the long straight proboscis at once distinguish 

 them. The two remaining families dealt with in this 

 volume are of small extent, and perhaps of less 

 interest than the two first. The Diptera are a some- 

 what neglected order of insect, but are more studied 

 now than formerly, and we are sure that Prof. Lund- 

 beck's work will be found very useful to English 

 entomologists, for whose benefit it is written in their 

 own language. The order Diptera is probably the 

 largest of the seven great orders of insects except the 

 Hvmenoptera, and we wish Prof. Lundbeck long life 

 that he may be able to complete the \\ork which he 

 has so well begun. 



Moving Loads on Railway Uiiderhridgcs, including 

 diagratns of Bending Moments and Shearing 

 Forces, and Tables of Equivalent Uniform Live 

 Loads. By H. Bamford. Pp. iv + 78. (London : 

 Whittaker and Co., 1907.) Price 45. 6d. net. 

 This is a reprint in book-form, with additions, of a 

 series of articles which appeared in Engineering in 

 the autumn of igo6. Those who have had any experi- 

 ence of such work will know how tedious is the 

 process, as usually conducted, of determining the 

 maximum straining actions on a railway girder sup- 

 ported at the ends, due to any given type of train 

 load, and will appreciate the methods here given, 

 which are characterised by directness, simplicity, and 

 comparative brevity. The author uses analytical 

 computation with systematic tabulation, and also, as 

 an alternative method, graphical diagrams based on 

 a clever adaptation of the ordinary bending and 

 shearing force diagrams. By one or other of these 

 methods, and especially the latter, the " equivalent " 

 uniformly spread loads for both maximum bending 

 moments and shearing forces arc quickly and easily 

 determined. The investigation is limited to the force 

 actions on the bridge taken as a whole, and does not 

 consider separately the resistances offered by the 

 platform and main girders, but so far as the subject 

 is dealt with the author is to be congratulated on 

 having produced a most useful and practical work. 



Practical Floor Malting. By Hugh Lancaster. 

 Pp. iv-|-2ii ; with numerous illustrations. (London : 

 The Brewing Trade Review, 1908.) Price 12s. 6d. 

 net. 

 Considering the economic importance of floor malt- 

 ing in this country, it is somewhat remarkable that no 

 work on the subject possessing any claim to thorough- 

 ness has hitherto been published. We hoped to find 

 that the present book filled the void, but although it 

 is a useful addition to the literature of malting, it 

 cannot in its present form be regarded as a complete 

 technical treatise on the subject. The author is evi- 

 dently thoroughly conversant with the practice of floor 

 malting, but owing, nresumably, to lack of literary 

 experience, he has not done justice to his knowledge, 

 and the book is marred by many signs of hasty 

 writing. As it stands, however, the work is dis- 

 tinctly a useful one, and we have nothing but praise 

 for the ten collotype plates it contains which illus- 

 trate the differences existing between the various types 

 of barley employed in malting. These plates are of 

 exceptional merit, and add very much to the value 

 •if the book from a technical point of view. 



NO. 2040. VOL. 79] 



LETTERS TO THE EDITOR. 



[The Editor docs not hold himself responsible for opinions 

 e.xpresscd by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous comnuinications.] 

 Students' Physical Laboratories. 



If a protest is not made, 1 see some danger of the 

 pioneer work done towards organising physical laboratory 

 work for students in University and King's Colleges in 

 London being inadvertently ignored, and everything of 

 that kind attributed to Finsbury. Probably, indeed, the 

 sound work unobtrusively done in early days is known 

 to very few. Allow me to say, therefore, from personal 

 knowledge, that students were admitted to physical 

 laboratory work in these colleges before J872 — in one of 

 them, I believe, in 1866 — and that the course of quanti- 

 tative laboratory instruction through which I was myself 

 put by Prof. Carey P'oster, in topographical circum- 

 stances of some difficulty, was of high value ; and, indeed, 

 reached a standard of accuracy not readily eclipsed in any 

 students' laboratory with which I have since become 

 acquainted. 



To take a single instance, Carey Foster described his 

 " bridge " method in 1872, and students were regularly 

 familiarised with it. I remember also making a series 

 of well-designed experiments on moments of inertia, 

 on the kinetic torsion of wires, and on determinations of 

 g by falling bodies and chronograph as well as by pendu- 

 lums. We also used to measure E.M.F. by the potentio- 

 meter method, then called Poggendorff 's ; while other prac 

 tical subjects were conduction of heat, rates of cooling, 

 specific and latent heats, on the lines of Regnault ; absolute 

 density of liquids, by weighing in them a gauged ivory 

 sphere, density of gases, &c. ; a long series on magnetic 

 moments and terrestrial magnetism in the light of Gauss's 

 theory ; the u >ual optical measurements and some less usual ; 

 Siemens's pyrometer (then under test for a British Associa- 

 tion Committee) ; much work with a tangent galvanometer 

 and resistance boxes — then comparatively new — on Ohm's 

 and Joule's laws; measurements of electrochemical equiva- 

 lents, &c., &c. ; all before 1875. In one of the last-men- 

 tioned determinations a platinum basin was used and a 

 weighable deposit obtained, very much on lines afterwards 

 rendered secure and classical by Lord Rayleigh. 



Indeed, I went through most of the things done in 

 laboratories to-day which do not involve instruments of 

 more recent date, and in 1875 we published a joint paper, 

 '* On the Flow of Electricity in a Plane," wherein the 

 equipotential lines were plotted by an experimental method 

 handier and more accurate than had been possible in pre- 

 vious observations of the kind — a method invented en- 

 tirely by Carey Foster (see Phil. Mag., December, 1875, 

 §§ 47-50, with an incomplete continuation in 1876). 



It is true that in those days attention was paid to thi? 

 principles of pure physics rather than to technology ; 

 and undoubtedly, as technical work became prominent, 

 other laboratories went far ahead in such subjects as the 

 design of practical measuring instruments and in facilities 

 lor large-scale work. 



But without suggesting for a moment that a word too 

 much has been said in praise of the energetic pioneers in 

 the field of practical work and electrical engineering, it will.. 

 I feel sure, be admitted that to say (as on p. 74) 'that 

 before 1875 only five persons had experimented in elec- 

 tricity in Great Britain, that the Finsbury system was 

 radically different from anything which previously existed, 

 and that before 1879 professors had merely shown experi- 

 ments at the lecture table, is to make statements which 

 involve a considerable amount of exaggeration, and un- 

 intentionally misrepresent the facts. 



I take it that the novelty at Finsbury chiefly lay in 

 the permanent installation of a number of ingenious ap- 

 pliances, whereby a crowd of evening students could be 

 put through a useful course of practical work, such as 

 would give them some preliminary idea of measuring 

 physical quantities, and infuse their otherwise abstract 

 notions with something definite and concrete, without the 

 necessity for periodical preparation and clearing away by 

 an impracticably large assistant staff. 



