June 22, 191 1] 



NATURE 



547 



fully treated, and many of the testing galleries 

 employed for investigating the safety of explosives in 

 coal mines are described. Many suggestions for the 

 substitution of perfectly safe bodies in lieu of true 

 explosives for this purpose are referred to. Among 

 these may be noted the use of quicklime and its ex- 

 pansion on slaking; cartridges charged with liquid 

 carbon dioxide or oxygen; but one of the most 

 interesting methods was that introduced by M. Linde 

 for the use of liquid air, in some cases a paper car- 

 tridge filled with kieselguhr and saturated with petro- 

 leum was then dipped in liquid air, the firing being 

 carried out by a Bickford fuse or fulminate detonator. 

 When the Simplon Tunnel was commenced in 1899 

 several attempts were made to utilise the explosive 

 force of liquid air mixed with flour for blasting the 

 rocks, but with unfavourable results. Liquid air 

 alone, in metal cartridges, has also been tried for 

 bringing down coal, but the author concludes that it 

 does not seem an economic success. 



Of more general interest is the important question 

 of modern smokeless powders as propellants for mili- 

 tary purposes. The Powers are fairly evenly divided 

 in the choice between a gelatinised nitrocellulose 

 powder or a nitrocellulose-nitroglycerine colloid. At 

 one time the majority favoured the simple nitrocellu- 

 lose powder, which is still retained by France and 

 Russia, whilst Great Britain remains faithful to cor- 

 dite, and Italy to ballistite. Germany may be said to 

 be in a transition stage, for whilst employing a nitro- 

 cellulose for field guns, for the larger naval weapons 

 a powder very similar to our modified cordite is 

 employed. 



All have had troubles to face with premature de- 

 composition in magazines, and especially France. At 

 Saigon in 1897 a quantity of poudre B ignited with- 

 out setting fire to some black powder stored near by. 

 19,500 kilogrammes of this same powder had burnt 

 with little damage in the previous year at the Saint- 

 Medard factory, but the Jena disaster will ever be 

 most prominently associated with this particular ex- 

 plosive, to which, in the autlior's opinion, it was 

 wrongly attributed, whereas the special Commission 

 appointed to inquire into the cause of this disaster 

 believed it to be due to spontaneous decomposition 

 of poudre B. 



The instability of smokeless powders has led to the 

 introduction of "stabilisers," the action of which is 

 to absorb the oxides of nitrogen resulting from decom- 

 position, which oxides, if present uncombined, greatly 

 accelerate further decomposition. The author men- 

 tions a number of these, which include urea (American 

 powder), diphenylamine (ballistite and the French 

 powder BBo, first introduced after the ]ena disaster), 

 amyl alcohol (in the most recent French powders, 

 AM2 and AMg), which appears to give excellent re- 

 sults. In cordite the vaseline acts as the stabiliser, 

 although originally introduced for quite other pur- 

 poses. It does not follow that for powders containing 

 both nitroglycerine and nitrocellulose two stabi- 

 lisers, one for each constituent, should be provided, as 

 the author appears to think necessary. 



Summarising the question of relative stability of the 

 NO. 2173, VOL. 86] 



two classes of propellants the statement is made that 

 gelatinised nitrated cottons possess more stability 

 than the nitroglycerine-nitrocellulose powders, and 

 although the velocity of the projectile is lower for the 

 same charge they have marked advantages in lower 

 temperatures on detonation, less erosive action on the 

 rifling of the guns, and give less smoke. In view of 

 the troubles experienced with simple nitrocellulose 

 powders, the claim of their superior stability, ^er se, 

 to cordite is open to question. 



On the whole the volume will be found a useful 

 work of reference on the composition, manufacture, 

 and application of explosives for practically all pur- 

 poses. It is more essentially a book suited to the 

 requirements of the engineer or mining expert, and 

 would not afford much information to the chemist or 

 those engaged in the manufacture of explosives. 



J. S. S. B. 



A STATE MEDICAL SERVICE. 



The Dawn of the Health Age. By Dr. B. Moore. 

 Pp. ix + 204. (London : J. and A. Churchill; Liver- 

 pool : The Liverpool Booksellers' Co., Ltd., 1911.) 

 Price 35. 6d. net. 



THIS is a remarkable and noteworthy book, 

 powerfully written, and very convincing on 

 most of the points raised. Its aim is to demonstrate 

 the necessity for entirely remodelling the present 

 system of medical service, in the interests of the 

 whole community. It goes far to show that hundreds 

 of thousands of lives and millions of money could 

 be saved annually if diseases were attacked on more 

 scientific principles; and the main theme is that we 

 allow diseases to invade and enfeeble us, and then 

 make an attempt (often a poor one) at cure, instead 

 of concentrating our efforts on prevention. 



The first chapter is headed, " How we tinker with 

 disease instead of stopping it." Therein it is pointed 

 out that concerted, statesman-like action is demanded. 

 The present undisciplined mob must be converted 

 into a disciplined army; and there are signs fore- 

 shadowed by legislation dealing with some of the 

 great problems of social reform, commencing with 

 invalidity insurance and reform of the Poor Law, 

 that we are turning in this direction. The organised 

 army of doctors would cost the nation from eight to 

 ten millions a year — an amount which is at present 

 exceeded, but in a nationalised medical service the 

 money would be paid through different channels. 

 Under the new regime, medical treatment would be 

 as free to everyone as is the education of to-day, and 

 everyone would be bound to accept medical treatment 

 in his own interests, just as to-day he accepts the 

 education of his child. The author estimates that 

 tuberculosis costs the country i6,ooo,oooJ. a year, 

 and that it can be eradicated for an expenditure of 

 less than io,ooo,oooI. a year for ten years, further 

 expenditure almost stopping at the end of that period. 

 He furtlier maintains that tuberculosis and prevent- 

 able infantile mortality together cost us more than 

 double the price of an effectual national service for 

 their prevention. 



