DISCOVERY 



59 



objections. The cylinders were not only very cumber- 

 some, but they were extremely vulnerable. (They 

 went off when struck by an enemy shell, even though 

 they weren't manufactured for that purpose.) In 

 addition the opportune discharge of gas depended on 

 the slope of the country in front of the front line, and on 

 the shape of the trenches and on the direction and 

 velocity of the wind. Even then, after much palaver 

 over the 'phone, and the alteration of the zero hour 

 because of " conditions," the discharged gas not 

 infrequently did some harm to our own troops as they 

 went over to the attack. 



In consequence shells, trench-mortar bombs, and even 

 hand grenades were filled with poison, and then fired 

 into the enemy's midst. These had no back effect, 

 and so long as they fell approximately at the chosen 

 spot they were effective. 



For success in attacking by gas, one of the most 

 important things was to maintain a high concentration 

 of the poison in the air around. One part of a gas in a 

 thousand of air when maintained was considered a high 

 concentration, and indeed one part in ten thousand 

 with most poison gases was quite effective. One would 

 imagine that the denser the gas the more deadly it 

 would be, other things being equal, because it would 

 lie in trenches and in shell-holes where soldiers were ; 

 but it must be remembered that all poison gases soon 

 became very diluted by the air round, and the density 

 of the mixture therefore, after a time, could not be 

 very different from that of air itself. 



What did the scientific organiser of gas warfare con- 

 sider to be the most important features of a gas ? First 

 of all, the ease with which the necessary large quanti- 

 ties of the gas could be made, and the convenience with 

 which it could be transported ; secondly, the effect 

 of the gas when inhaled by the soldier, and the diffi- 

 culty the other side might have in providing adequate 

 protection against it. 



The best known of the gases used were chlorine, 

 phosgene, mustard gas, and chloropicrin, but many 

 more, described by long chemical formula and even 

 longer chemical names, were used by both sides. The 

 element of surprise was an important tactical point, 

 and it was considered clever to send over a new gas 

 of which the other side was ignorant, and against 

 which they had provided their soldiers with no 

 protection. 



Chlorine, as everyone knows who has inhaled it, 

 even in small doses, has a most irritating effect on the 

 throat and lungs. It is, however, a simple and honest 

 poison. You may see it coming, and so avoid it. 

 Further, either you get it or you don't get it. With 

 phosgene, on the other hand, you are never quite sure 

 where you are. Although its effect is less irritating 

 than chlorine, it has a delayed physiological action. 



[Continued on p. 60 



Editors 



Editors and Publishers don't : 



care how, where, or why j 



matter submitted to them is [ 



i ^ wrong. They are not con- \ 



E r\ 7 ■ cerned in putting it right. 

 I 111 II I They are only concerned in 



i *^>'** * getting what they want. 



I ^^ Fortunately, the new writer [ 



i ■ ^ mM^% to-day can begin with all the 



i ^^cllC* practical knowledge, hints, 



I tips, and advice, that he i 



i might otherwise fail to discover in a life-time. ] 



I Experience Systematised. The P.C.C. System is \ 



I based on the co-ordinated and concentrated experi- i 



i ence not of one writer, but of many writers who have I 



I made good. \ 



i Personality, Ambition, Industry. 



i The P.C.C. does not endow you with personahty, ; 



i ambition, or industry, but, given the '"three essentials," = 



I it can tell you how to put your work into saleable form ; 



I — and sell it. The P.C.C. editorial revision of your = 



1 writing and systematic training will save you years of E 



I floundering — and show you the shortest possible cut to i 



= success, for the lowest possible fee in the least possible = 



i time. i 



i // IS itsclfss to send: The right MS. at the right i 



I time to the wrong people. The right MS. at the E 



I wrong time to the right people. The right MS. at = 



I the wrong time to the wrong people. i 



I The P.C.C. teaches you how to send : The right i 



i MS. at the right time to the right people. There is | 



I a prodigious demand for stories — never ending, ever = 



i growing, never satisfied. Editors have now to adver- i 



i tise for a suitable copy. Those who cannot sell articles | 



i and stories may learn why. Gratis criticism and advice. = 



\ Send short specimen MS. with stamps for return to Editor- E 



z in-Chief. Practical Correspondence College, Ltd., 16 Thanet = 



i House, -Strand, W.C.2. . I 



I Scholarship Courses of Postal Training at reduced = 



E fees reserved for applicants whose specimens show un- i 



I usual promise. i 

 ^luiuuiuuiiiiiiiiiiiiiuiiuiuiuiuiuiuiiiiiiiiiiiiiiiiiiiiuiiiiiiiitiiiiiiiiiiiiitiiiniiiiiitiiiuiiikT- 



THE HIDDEN HAND. 



A Contribution to the 

 History of Finger Prints. 

 By HENRY FAULDS, L.R.F.P.&S., F.R.A.f. 



Autbor of ■■Guide to Finger-Print IdentlflcaUoD " and "Dactylography," etc. 

 •' Xo Utter example 0/ this tardiness could le /ouiiu than the story 0/ 

 the valtte 0/ Jingcr prints as identity-marks. The discovery 0/ this most 

 important means 0/ identification^ which is ncnu almost universally 

 applied, is usually credited to a frenchman, M. Bertillon ; whereas the 

 sole responsibility for this invaluable method rests with a member 0/ our 

 own race attd profession. Dr. Henry FauMs.iuho expounded it in ^^ Nature," 

 at considerable length, as long ago as 1 880. Dr. Faulds brought the jnetlwd 

 to the notice of various officials at that time, all of whom either pooh- 

 foohed it or damned it with faint and patronising praise. At any rate 

 nothing was done ; and although there can be no jnanner of doubt that Dr. 

 Henry Faulds was the first to expoutul the method, the credit has been 

 given to a variety of other people. Those of my readers who wojtld like to 

 read tlu whole interesting story, impartially but most convincingly set fo* th, 

 should read tlit little pamphlet which Dr. Faulds has written on the sub- 

 ject. It is called ' The Hidden Hand: "— Mkdkal World. 



ed. post tree to any address. 

 OR. FAULDS, Regent House, Hanley, Stoke-on.Trerft. 



All applications for Advertisements to be made to 

 The Advt. Manager, 



" DISCOVERY," 

 16 Regent Street, London, S.W.I. 



Telfphont: REGENT 113 



