i8 



NATURE 



[May 5, 1898 



World. If a fluorescent screen is protected from the direct 

 action of rays emitted by a tube, by means of an opaque plate, a 

 slight fluorescence is nevertheless seen when the tube is in 

 action. Rontgen has now shown that this is due to the fact 

 that the air around the tube gives forth X-rays. The brightness 

 of a screen illuminated with rapidly intermittent rays depends 

 on a number of properties which he enumerates. The X-rays 

 from a platinum focus plate which are most active for showing 

 mages are those which leave the plate at the greatest angle, 

 but not much greater than 80° ; thick plates have a relatively 

 arger transparency than thin ones, that is, the specific trans- 

 parency of a body is greater the thicker the body ; the same 

 body has different transparencies with diff'erent tubes, "soft 

 tubes " being those requiring a small potential, and " hard tubes " 

 those requiring a high one. The quality of the rays from the 

 same tube depends on : the way in which the interrupter 

 works, the insertion of a Tesla transformer, the vacuum, other 

 processes in the tube which are not yet fully investigated. The 

 smallest pressure at which X-rays are produced is very likely 

 below o*ooo2 mm. of mercury. The composition of the rays 

 from a platinum anode depends largely on the element in the 

 current ; the quality of the rays does not change with changes 

 of the primary current, or at least very little, but the intensity is 

 proportional to the strength of the primary current between 

 certain limits. The following conclusions are stated : the 

 radiation consists of a mixture of rays of different intensity and 

 absorbability ; the composition depends greatly on the time 

 element in the current ; the rays produced by the absorption of 

 bodies are different for different bodies ; as X-rays are produced 

 by kathode rays, and as both have common properties, it is 

 probable that both processes are of the same nature. If two 

 screens are illuminated with two tubes of different hardness, the 

 illumination being made equal, and if then replaced by photo- 

 graphic plates, the one illuminated by the harder tube will be 

 blackened much less than the other ; rays which produce equal 

 fluorescence can be photographically quite different ; the usual 

 photographic plates are very transparent for X-rays (in a pile of 

 ninety-six filaments exposed for five minutes the last one showed 

 photographic action) ; the eye is not entirely passive to X-rays. 



Prof. Louis Boutan, lecturer on zoology at the Sorbonne, 

 contributes to the Century Magazine (May) an account of his 

 experiments in submarine photography. To procure photo- 

 graphs under water. Prof. Boutan uses a camera enclosed in a 

 water-tight case, a blue glass being arranged in front of the 

 lens to suit the conditions of submarine illumination, and so 

 give a picture having pleasing contrasts. He descends under 

 water in a diver's costume, and the camera is sent down to him 

 from an anchored boat. The spot to be photographed is then 

 selected, and the exposure is made in precisely the same way as 

 on land. When no artificial light is used, submarine photo- 

 graphs require a rather long exposure, the time often extending 

 to twenty-five minutes, and depending upon the depth of the 

 water. Four reproductions of photographs obtained at depths 

 from six and a half feet to sixteen and a half feet, accompany 

 Prof. Boutan's article, and they are sufficient to show that sub- 

 marine photography can produce useful results. It is estimated 

 that not more than one hundred square metres of area can be 

 photographed under water, but even with this limitation the 

 pictures obtained will contain more valuable information than 

 divers can furnish. The problem to be solved is to construct 

 an apparatus which will take photographs in artificial light in 

 any depth of water without needing a submarine photographer 

 to manipulate it. V 



The immunity of bee-keepers from the effects of bee-poison, 

 forms the subject of a paper, by Dr. Langer, read before the 

 sixty-ninth Congress of German Naturalists and Physicians in 

 NO. 1488, VOL. 58] 



Brunswick. The author sent circulars to all parts of the 

 country addressed to bee-keepers, and from the answers he 

 received he has compiled some interesting statistics. One 

 hundred and forty-four bee-keepers stated that they were im- 

 mune to the sting of bees, nine mentioning that they were 

 naturally immune to the poison, whilst twenty-six replied that 

 they could not acquire immunity. The number of bee-stings 

 necessary to produce the much-desired immunity appears to 

 vary considerably, sometimes thirty being sufficient, but in 

 other cases as many as 100 being necessary to accustom the 

 system to the poison. The remedies applied range over a large 

 variety of substances, and include tobacco juice, French brandy, 

 rum, water, spirits of ammonia, seltzer water, acetate of 

 alumina, loam, saliva, cognac, besides massage and heat. The 

 most favourite means of dealing with bee-stings appears to be 

 spirits of ammonia. Dr. Langer states that a 5 per cent, solu- 

 tion of permanganate of potash will counteract the poison, and 

 he recommends an injection of a 2-5 per cent, solution of this 

 substance. Bee-poison is extraordinarily resistant to both 

 dessication and heat, whilst it is quite unaffected by additions of 

 alcohol. It used to be commonly supposed that the irritating 

 nature of bee-poison was due to the presence of formic acid ; but 

 inasmuch as it can withstand heat and retain its poisonous 

 activity, which would effectually volatilise the formic acid were 

 it present, this idea must be abandoned. The opinion now 

 appears to be that the toxic substance present partakes of the 

 nature of an alkaloid. 



A COPY of the Act of Incorporation, bye-laws, and list of 

 officers of the recently-established Washington Academy of 

 Sciences has been sent to us. The particular business and 

 objects of the Academy are stated to be the promotion of 

 science, with power to acquire, hold, and convey real estate and 

 other property, and to establish general and special funds ; to 

 hold meetings ; to publish and distribute documents ; to conduct 

 lectures ; to conduct, endow, or assist investigation in any de- 

 partment of science ; to acquire and maintain a library ; and, 

 in general, to transact any business pertinent to an Academy of 

 Sciences. The Academy will act as a federal head of the 

 affiliated scientific societies of Washington, with power to 

 conduct joint meetings, publish a joint directory and joint 

 notices of meetings, and take action in any matter of common 

 interest to the affiliated societies. The term "affiliated 

 societies " at present covers the Anthropological, Biological, 

 Chemical, Entomological, National Geographic, Geological, 

 Medical, and Philosophical Societies, each society nominating a 

 vice-president. The President of the Academy is Mr. J. R. 

 Eastman, and the Secretary Prof. G. K. Gilbert. 



Curators of museums know that the papers read at the 

 annual meetings of the Museums Association, and the discussions 

 which take place upon them, are serviceable in indicating the 

 best systems of classification and arrangement of specimens, and 

 in evoking expert opinions upon museum technique. The 

 Report of the proceedings of the Oxford meeting of the Associ- 

 ation, edited by Mr. James Paton, has just been published by 

 Messrs. Dulau and Co., and from it much valuable information 

 can be gained by the officers of local museums. Among the 

 contents is an address by the president. Prof. E. Ray Lankester, 

 F.R.S., and papers on the methods of setting and labelling 

 Lepidoptera for Museums, by Prof. E. B. Poulton, F.R.S. ; 

 the arrangement of the mineral collection in the University 

 Museum, Oxford, by Prof. H. A. Miers, F.R.S. ; the arrange- 

 ment of ethnographical collections, by Mr. F. W. Rudler ; 

 popular museum exhibits, the relation of museums to elementary 

 education, and a description of the Colombo Museum. Opinions 

 and conclusions based upon successful experience are always 

 valuable, therefore this report of the Museums Association will 



