September 15, 1923] 



NA TURE 



;95 



per second within the capillary. A very small 

 number of such particles were actually observed with 

 most of these substances, the scintillations being, 

 however, too few for anything definite to be said at 

 present regarding their origin. 



Having regarded quartz as an ideal non-active 

 substance to be used in these experiments, we were 

 somewhat disappointed at finding, with a more thin- 

 walled capillary than the others, a relatively large 

 number of faint but distinct scintillations from the 

 unlined part of the quartz, the rest of the capillary, 

 lined with a thin coating of scandium oxide, giving 

 no such scintillations. These scintillations practically 

 disappeared when the total absorption was raised 

 from 10 to 15 cm. by interposition of a mica filter. 

 Similar results were afterwards obtained with other 

 thin-walled capillaries ; the absorption curve for the 

 H-particles is being at present more accurately deter- 

 mined in this Institute. 



Considering the high purity of the quartz, and the 

 care taken to free the emanation from moisture and 

 other hydrogen contaminations, we see no other way 

 to explain this observation than by assuming silicon 

 to give off H-particles of the maximal range just 

 stated. 



We have recently constructed a different emanation 

 vessel in which the substances to be examined are 

 spread in thin layers over copper foil of about 4 cm. 

 absorbing power, forming the bottom of a narrow 

 emanation trough, the emergent H-particles being 

 counted from below with a scintilloscope. In this 

 manner we have obtained fairly conclusive evidence 

 that H-particles are also given off from the following 

 elements : 



Silicon, as element, approximate maximal range 



18 cm. air. 

 Beryllium, as oxide, approximate maximal range 



12 cm. air. 



Magnesium, as oxide, approximate maximal range 



13 cm. air. 



Lithium, as carbonate, approximate maximal range 

 10 cm. air. 



With lithium the results are less definite than with 

 the others, mainly owing to the difficulty of excluding 

 contamination with hydrogen compounds. 



Blank experiments with only the bare copper foil 

 (which had previously been bombarded with cathode 

 rays in a vacuum to remove occluded gases) showed a 

 much smaller number of H-particles. and, judging from 

 the absorption curve, due to " neutral " H-particles. 

 We are having the apparatus reconstructed so as to 

 eliminate errors from this source. 



A more detailed description of our experimental 

 arrangement is being published shortly. The emana- 

 tion capillaries will be used in this Institute also for 

 studying atomic disintegration by the Wilson method. 



Our results seem so far to indicate that the hydrogen 

 nucleus is a more common constituent of the lighter 

 atoms than one has hitherto been inclined to believe. 



Gerhard Kirsch. 

 Hans Pettersson. 



Institut fur Radiumforschung, Wien. 



The Menace to Civilisation : an Appeal to 

 Men of Science. 



May I ask the hospitality of the columns of Nature 

 for an appeal to men of science throughout the world ? 



The enthusiastic pioneers of Victorian times, whose 

 work underlies the fabric of modern science, always 

 thought of themselves as beneficent agents. In them 

 scientific ardour was joined with devotion to the 

 welfare of humanity. They saw science releasing men 



from toil, improving their health and comfort, spread- 

 ing toleration and promoting international under- 

 standing. Some part of these hopes has been realised, 

 while others we may yet hope to realise. 



But we are now faced with pressing and imminent 

 dangers which the Victorians could not foresee. 

 Science has immensely increased the destructive 

 powers of mankind, without in the least diminishing 

 their readiness to use those powers. It has been 

 stated by a member of the Government that since 

 the Armistice, "in the different civilised countries" 

 no less than five kinds of poison gas have been 

 invented, each more deadly than any used in the 

 War. This sentence is not quoted to illustrate the 

 conception of civilisation current among politicians, 

 but merely to indicate the present tendency of re- 

 search in one direction to amplify the means of 

 destruction which will be available in the next war. 

 At any moment a caprice of politics, or a vicissitude 

 of international trade, may plunge us into a war 

 which we shall be quite unable to prevent. In that war, 

 which every year's delay will make the more deadly, 

 the most incredible powers of destroying not only 

 human life, but the whole apparatus of our civilisa- 

 tion, will be entrusted to boys of eighteen, and, for 

 all we know, to African negroes. Science will have 

 crushed the civilisation that gave it birth. 



If the forces now at work are allowed free play 

 this result may reasonably be regarded as not only 

 a probability, but also a practical certainty ; quite as 

 certain, for example, as was the French Revolution 

 when Lord Chesterfield prophesied its coming. 

 Whether the storm will burst on us or on our grand- 

 children we cannot tell, but that the heavens are big 

 with it is plain to see. The really desperate part of 

 the position is that, so far as Europe goes, the total 

 collapse of all that we have learnt to know as civil- 

 ised life is regarded with almost complete indifference. 

 Each nation is on a par with the man in ^Esop, 

 whose only care, when the ship was sinking, was to 

 take up such a position that he could have the pleasure 

 of seeing his enemy perish before he succumbed him- 

 self. So long as we have an Air Force which can 

 destroy the other people's capital at least as soon as 

 they destroy ours, we are quite happy, so far as 

 Parliament and the Press are concerned, at any rate. 

 Is it too much to hope for something better from 

 men and women who have had a scientific training, 

 who have learnt in their work the essential fellowship 

 of all servants of science, and whose consciences must 

 tell them that it is their efforts, in whatever spirit 

 they may have been conceived, which are now in danger 

 of being directly responsible for the most appalling 

 disaster in human history ? It is not necessary to 

 speak of the terror-stricken multitudes in the doomed 

 cities, the screams of women and children in helpless 

 anguish, the tragedy of Pompeii repeated on a 

 thousand-fold scale ; nor does it take much imagina- 

 tion to foresee the red ruin and breaking up of laws 

 that will follow : can any one think that a world that 

 has suffered such unimaginable horrors from science 

 will hereafter tolerate it in the hope that it may do 

 something to alleviate cancer ? In destroying civil- 

 isation, science will also destroy itself. 



The only hope for the world lies in the men of 

 science. It is their paramount duty to see that the 

 knowledge they win is used only for the good of their 

 race and not for its destruction. The day is past 

 when they can simply throw their discoveries out 

 into the world and let them take their chance. In 

 my opinion the only possible salvation lies in the 

 immediate formation of an international league of 

 men and women of science who shall pledge them- 

 selves not only to fight against war, but to refuse to 



NO. 281 I, VOL. 112] 



