42: 



NATURE 



[June 3, 1920 



was consequently very impure. Three thermometers 

 were placed apparently at a distance of about 4 ft. or 

 5 ft. from the prism — one in the spectrum, and the 

 other two in the shadow beside it — and the difference 

 of temperature produced by the rays was noted. The 

 bulbs of the thermometers were blackened ; one of 

 them measured J in. in diameter, but the others were 

 smaller. One and a half inches beyond the red there 

 was a rise of 3!° in 10 min., i in. beyond the red 5:^° 

 in 13 min., and \ in. beyond the red 6^° in 10 min. 

 In the violet there was a rise of 1° in 15 min. The 

 sf>ectrum was about 3 in. long, and the heat rays 

 could be detected a distance of 2J in. into the infra- 

 red. R. A. HousTOUN. 

 University of Glasgow, May 19. 



Anti-Gas Fans. 



In a note in Nature for May 13 you intimated 

 that my "allegations" concerning the treatment of 

 my anti-gas fans by the War Office and the suffering 

 and loss of life thereby entailed could not be accepted 

 without question, and you called upon the " well- 

 accredited men of science," who, you say, largely 

 staffed the Anti-Gas Service, to make a "plain state- 

 ment of the facts." I waited to see if such a state- 

 ment would be forthcoming, though I judged it 

 scarcely likely; and now, since it has not appeared, 

 I ask you, in fairness, to grant me space for a few 

 remarks on your note. 



You suggest that such an indictment as I have 

 brought against the War Office, reinforced as it is 

 with their own letters, reports, and pamphlets, can be 

 refuted by the bare word of certain "well-accredited 

 men of science." I pass over the implied slur on 

 myself of being less well-accredited than they, my 

 word of smaller value than theirs. No unprejudiced 

 person who has read that indictment and that evi- 

 dence with any care will agree with you that they can 

 be thus easily disposed of. 



In my dealings with the War Office I had to do 

 with innumerable officials, some of them men of 

 science, most not. From their behaviour I judged 

 the larger number (and the exceptions were not, I 

 regret to say, men of science) to be mere puppets, 

 acting under the direction of some leading spirits 

 behind. Who those leading spirits were I had no 

 means of knowing; I was carefully kept in the dark. 

 You, sir, intimate, that they were "well-accredited 

 men of science." If this was indeed so, then surely 

 you will agree with me that, for the sake of science 

 even more than in the interests of the nation at large, 

 it Is essential that this matter should not be hushed up, 

 but that a public inquiry should be instituted. I am 

 not only willing, but also most anxious to submit my 

 case to some impartial tribunal. Will the men of 

 science whom you have asked to speak, but who do 

 not answer, come out into the open and join with me 

 in demanding such an inquiry? If not, both the 

 world of science and the general oublic will know 

 what to think. Hertha Ayrton. 



41 Norfolk Square, Hyde Park, W., May 23. 



[We did not express an opinion upon the charges 

 made bv Mrs. Avrton, but limited ourselves to a state- 

 ment of the indictment, and pointed out that itwas 

 reallv directed against the men of science associated 

 with the Gas Service of the Army. Possibly these 

 officers are not free to enter into a discussion of 

 reasons for the neglect of the use of the fans, and 

 nothing short of a public inquiry will elicit the whole 

 of the facts in regard to them.— Ed. Nature.] 

 NO. 2640, VOL. 105] 



A New Method for Approximate Evaluation of Definite 

 Integrals between Finite Limits. 



The subject has a particular interest for naval 

 architects, inasmuch as the majority of calculations 

 relative to displacement, stability, strength, etc., of 

 ships involve the finding of areas and volumes 

 bounded by curved lines and surfaces. 



The particular rule enunciated by Mr. A. F. Dufton 

 in Nature of May 20 has been in use at this college 

 for some years, and gives very accurate results in 

 obtaining areas and volumes, and also, by a further 

 application, the positions of their centres of gravit}-. 



The method of its derivation was from one of 

 Tchebycheff's rules, /(x) in this particular case is 

 taken as (a+bx + cx^ + d:!c' + ex*). It can readily be 

 shown that the value of 



\'Ax)dx = i[/(.r,) +/(-^-2) +/(-^-3) +/(^4)], 



where 



i;A-i = 2, 2.^1- = *, 2.ri3=i, 2.11*= i, 



whence :v;i = o-i027, :t2 = o-4o62, X3 = o-5938, and 

 %4 = 08973. The approximation to one-tenth, four- 

 tenths, six-tenths, and nine-tenths was obvious, and 

 all the more welcome because it is our usual practice 

 to divide the ship's half-length into ten sections. No 

 special sections have to be drawn, calculations being 

 readily made with the aid of the existing drawings. 



This rule was briefly referred to by Mr. W. J. 

 Luke at a meeting of the Institution of Naval Archi- 

 tects in 1915 (Trans. I.N. A., vol. Ivii., p. 210). 



The application of Simpson's ordinary rule to find 

 the area of a quadrant or semicircle, as quoted, 

 manifestly shows Simpson's rule at its worst, owing 

 to the wide divergence of the curve from the assumed 

 curve from which the rule is derived. Where curves 

 approximate to these forms, as in many sections of a 

 ship, it is common practice in the use of this rule to 

 interpose intermediate ordinates where the curve is 

 " steep " — relative to the base line — to get greater 

 accuracy. 



An interesting paper dealing with this subject and 

 giving a great variety of rules for approximate integra- 

 tion was read at the Institution of Naval Architects 

 in 1908 (Trans. I.N. A., vol. 1.) by Sir W. S. Abell 

 entitled "Two Notes on Ship Calculations." 



C. F. Merchant. 



Royal Naval College, Greenwich, S.E., 

 May 27. 



Applied Science and Industrial Research. 



Your correspondent Mr. J. W. Williamson says 

 in Nature of May 27 that much of my criticism of 

 the Department of Scientific and Industrial Research 

 "seems to lend colour" to current misconceptions of 

 industrial research, which he proceeds to construct 

 out of his own imagination, having first fathered 

 them on me, and then submits that the cause of 

 pure science is not well served by inconsiderate attacks 

 on the industrial research movement, such as he would 

 have it believed I made. I judge from this that he 

 was not present at the meeting, and I therefore wish 

 it to be known that the full text of my address to the 

 National Union of Scientific Workers can be obtained 

 bv forwarding a stamped addressed foolscap cover to 

 the General Secretary,' 19 Tothill Street, Westminster, 

 S.W.I. If Mr. Williamson will have the goodness to 

 read it and the full report of the meeting published in 

 the current issue of ttie Scientific Worker, the official 

 organ of the union, and then say, if he still desires, 

 what he objects to. it would help rather than confuse 

 the issue Frederick Soddv. 



