594 



NATURE 



[July 8, 1920 



difficult to understand why they survived only on the 

 western side of this barrier of land. 



The Meteorological Magazine for Jurfe deals with 

 the recent disastrous flood at Louth as completely as 

 possible at the time of going to press, and adds 

 somewhat to the account in Nature of June lo 

 (p. 468). The characteristic features are given of the 

 hot weather experienced over England during the last 

 week of May, which occasioned the development of 

 numerous thunderstorms, A disturbance, centred over 

 the Bristol Channel on the morning of May 29, 

 traversed the Midlands during the day. Little or no 

 rain fell on May 29 south of a line passing through 

 Plymouth, Reading, and Lowestoft, and none was 

 observed over the centre and west of Scotland. There 

 was more than an inch of rain over the greater part 

 of Lancashire, the West Riding of Yorkshire, Lincoln- 

 shire, and the east of Nottinghamshire. In Lincoln- 

 shire the rainfall was very severe. At Louth the fall 

 was only 1-42 in., but at Elkington Hall, three miles 

 to the west, the fall was 4-69 in., and of this 4-59 in. 

 fell in three hours. At Hallington, about two miles 

 south, 4-10 in. fell in two hours, when the gauge over- 

 flowed and the exact total fall was lost. Ten miles 

 further south, at Horncastle, 3-95 in. fell in three 

 hours. The magazine states that, according to 

 the Borough Surveyor, the Lud stream, normally 

 3 ft. wide and i ft. deep, jvas swollen to a 

 width of 52 yards and a depth of 50 ft. It 

 appears that the stream was temporarily blocked 

 with ddbris, and the flood was the result of the sudden 

 breaking down of this obstacle. The periodical has a 

 very suggestive and useful article on the ventilation 

 of instrument shelters by the Director of Armagh 

 Observatory. The general rainfall for May in Eng- 

 land and Wales was 117 per cent, of the average, 

 in Scotland 164 per cent., and in Ireland 145 per cent. 



-The report of the Imperial Wireless Telegraph 

 Committee (Cmd. 777, price 6d. net) contains an in- 

 teresting review of the capabilities of different 

 systems of wireless transmission for long-distance 

 working, and forms a striking vindication of the 

 powers of the thermionic valve, which it is proposed 

 to employ as the sole means of generating the waves 

 required for the chain of stations 2000 miles apart 

 which are recommended. We admire the courage of 

 the Committee in putting forward a system which, 

 in its own words, " departs widely from the general 

 direction of contemporary practice." It admits 

 that "the objects desired might perhaps be ^cured 

 by other and more conventional methods, but by none, 

 in our opinion, not involving an immediate capital ex- 

 penditure and a heavy annual loss which the scientific 

 progress of a few years might well prove to have been 

 unnecessary." Discussing the alternative systems, the 

 Committee dismisses even the latest developments of 

 the spark system as obsolete. The high-frequency 

 alternator system it characterises as "costly, difficult 

 to repair, and as yet insufficiently tested in pro- 

 longed operation." The arc system is described 

 as "pre-eminent at the present moment among 

 methods of long-range wireless transmission." Arcs 

 of greater power than 250 kw., however, present 

 elements of uncertainty, and apparently do not deliver 

 NO. 2645, VOL. 105] 



to the aerial a greater effective current than those 

 rated at lower powers. Although the valve system 

 cannot show the same degree of accomplished results 

 as any of the preceding, the Committee has evi- 

 dence of such rapid advances now being made that 

 it recommends its adoption without hesitation. It 

 has already been found that a group of three glass 

 valves delivering 2^ kw. into the aerial can effect 

 communication over two thousand miles. Silica 

 valves are noW designed by means of which, with 

 suitable grouping, 120 kw. will, it is hoped, be 

 delivered into the aerial. Owing to the greater purity 

 of wave-form of valve-generated over arc-generated 

 waves, this arrangement should be considerably more 

 effective than a 250-kw. arc, which does not really 

 deliver more than 120 kw. into the aerial. There are 

 several other advantages for valve working claimed 

 in the report which we have not the space to mention 

 here. 



The deposition of iron by electrolysis is a method 

 which has lately been employed to a considerable 

 extent for the purpose of " building up " worn and 

 under-gauge parts of both aeroplanes and guns. The 

 work, however, has not been done under proper scien- 

 tific control, and not infrequently defects have mani- 

 fested themselves in use in the iron thus deposited. A 

 paper dealing with some of these was presented by Mr. 

 W. E. Hughes at the recent meeting of the Iron and 

 Steel Institute. In his capacity as chief research 

 chemist to the Electrometallurgical Committee of the 

 Ministry of Munitions, Mr. Hughes had opportunities 

 of making extended observations upon the structure of 

 the electro-deposited metal. He found that it was 

 liable to contain pinholes, lumps, inclusions of foreign 

 matter, cracks, and "quasi-cracks," and that a given 

 specimen might present very marked differences of 

 structure. He concludes that these defects may 

 render the iron dangerous and unsuitable for en- 

 gineering purposes, but that they arise from causes 

 which can be largely eliminated by efficient control of 

 the deposition process. It is generally assumed that 

 electrolytic iron is a very pure product, but, as he 

 shows, this is by no means necessarily the case. Fur- 

 ther, it is usually assumed to be hard, and may indeed 

 be so, though not always. Whether the hardness, when 

 it occurs, Is due to included hydrogen is a question 

 which has not yet been settled. Mr. Hughes's investi- 

 gation has proceeded sufficiently far for him to enter- 

 tain decided doubts about this explanation. 



Messrs. Dulau and Co., Ltd., 34 Margaret Street, 

 W.I, have just issued an important catalogue 

 (No. 83) of secondhand books of science in the 

 departments of ornithology, entomology, general 

 zoology, geology and palaeontology, geography, travel, 

 and topography, botany and horticulture. Of the 

 1256 works listed many are out of print and not easily 

 obtainable. .The catalogue can be had free upon 

 request. 



Another of the useful catajogues (No. 403) of Mr. 

 F. Edwards, 83 High Street' Marylebone, W.i, has 

 reached us. It consists of descriptions of some seven 

 hundred works relating to Central and South America^ 

 and should be of interest to many readers of Nature. 



