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SCIENCE-GOSSIP. 



SCIENCE GOSSIP 





Messrs. R. and J. Beck, of 68, Cornhill, London, 

 have sent an artistic pamphlet, upon the use of the 

 " Frena " Camera. We understand Messrs. Beck 

 will forward a copy to anyone upon application. 



On the evening of February 28th, Mr. Frank 

 Sich, jun., and a companion noticed the zodiacal 

 light as " a blunt cone of whitish light extending 

 from the misty western horizon up towards, but 

 not so far as, the Pleiades." 



The death is announced of Surgeon-Major 

 George Charles Wallich, who died on March 31st, 

 in his 84th year. He was a Fellow of the Royal 

 Geographical Society, and wrote several impor- 

 tant papers on biology and the distribution of the 

 lower forms of animal and vegetable life. 



The North Kent Natural History and Scientific 

 Society lose by resignation their honorary 

 Secretary in Mr. H. Webb. He is followed by 

 Mr. Thomas W. Brown, a vice-President, who 

 appeals for new members and other assistance for 

 the Society. His address is 80b, Church Lane, 

 Old Charlton. 



A flock of about thirty sandgrouse (Syrrhaptes 

 paradoxus Pallas) have frequented a somewhat 

 limited area on the Lincolnshire Wolds since the 

 end of January. In the great invasion of sand- 

 grouse in 1888, the first record for that county, 

 was from the same spot, only in the month of 

 May instead of the begining of the year. 



The Egyptian Government have decided to 

 arrange a survey of the Nile, with the object of 

 determining the species of fishes inhabiting its 

 waters. The fishes obtained are to be sent to Mr. 

 Boulenger, the ichthyologist on the staff of the 

 British Museum. 



The Crystal Palace Company have arranged 

 to institute some experiments in fish culture with 

 the object of ultimately founding an English 

 School of Pisciculture. The chief experiments will 

 take place in the large aquarium, which has 

 been cleaned previous to being stocked with 

 several species of Salmonidae. The reservoir, lakes, 

 and fountain basins in the grounds will also be 

 utilised. 



One of the most artistic monthly journals we 

 have met with for some time is the Photo-Miniature, 

 which is devoted to general photographic informa- 

 tion. It consists of thirty-six pages of the 

 unusual shape of 8 in. x 5 in. and is bound in an 

 artistic cover. The frontispiece of No. 1 is a copy 

 of Franz Hals' " Portrait of a Man," in the 

 National Gallery, London. An article upon modern 

 lenses illustrated by a number of diagrams occupies 

 the whole of this first number, excepting a page 

 of notes, and a plate of a November day by Georg 

 Yeder, from the Berlin National Gallery. It is 

 published by Tennant and Ward, of New York, 

 and Dawbarn and Ward Limited, of London, the 

 price being 6d. net. 



CONDUCTED BY JAMES QUICK. 



Atmospheric Electricity. — Experiments have 

 been made recently by Pellatt to show to what 

 extent evaporation of moisture from the earth's 

 surface is responsible for atmospheric electricity. 

 By putting a very flat dish into electrical commu- 

 nication with a quadrant electrometer, and ob- 

 serving the loss of charge in a given time, both 

 when the dish was empty, and when full of water, 

 Pellatt found that this loss was 40 to 60 per cent, of 

 the original charge in one hoivr. There must, 

 therefore, be this loss of charge and a gain of 

 negative electrification by the air during the first 

 warm hours of the day. The reverse process 

 must set in after sunset. This consideration 

 agrees with actual observations, but the observa- 

 tions of the 4 a.m. minimiun and the 8 p.m. maxi- 

 mum have yet to be recorded. 



Electric Fish of the Nile. — This subject 

 formed the Friday evening lecture at the Royal 

 Institution on March 17, by Professor Gotch. The 

 Malapterurus,the fish discussed, is unlike the Gym- 

 notus and the torpedo fish, in that its electric organ 

 does not impede its motion. Professor Gotch 

 believes that the seat of its electromotive force is 

 in the nerve centre itself, and not the collection 

 of " plates " hitherto considered to be the electric 

 organ. These "plates " might be looked upon as 

 forming a condenser or a series of condensers, 

 charged at will by the fish. If so, they will 

 account for some of the discharge phenomena. 



Wehnelt's Current Interruptor. — A dis- 

 covery of great interest to electricians has 

 just been made by Dr. A. Wehnelt of Char- 

 lottenburg, and has taken a practical form in an 

 electrolytic contact breaker for rapidly intermit- 

 tent currents. Anyone who has worked with an 

 induction coil will have experienced the worry 

 that the ordinary form of contact breaker entails. 

 Most of the spring breakers continually " jam '* 

 and short-circuit, while mercury breaks require 

 much attention, and are poisonous. Dr. Wehnelt's 

 break consists essentially of a cathode of sheet 

 lead (any other metal will serve) and a platinum 

 wire in close proximity to it as an anode. The 

 two - electrodes are then arranged in a cell with 

 dilute sulphuric acid. When a suitable current is 

 sent through, a rapidly intermittent discharge takes 

 place between the two electrodes, the frequency 

 of break being sometimes as great as 1,700 per 

 second. So complete is the break of current, more- 

 over, that no condenser is requisite to the induc- 

 tion coil. For the satisfactory working of this 

 break it is best to use a high voltage, such as is 

 obtainable from electric light mains. The effi- 

 ciency of induction coils for Rontgen ray work is 

 considerably increased by the use of this arrange- 

 ment. Experiments made with this break show 

 that if the platinum anode is sealed into a glass 

 tube, the later is apt to break. This is probably 

 due to the intense heat just at the discharge point. 

 The use of an ebonite tube overcomes the difficulty. 



