July 22, 1920'! 



NATURE 



663 



out of hand and destroy an entire crop ; but, even so, 

 they exact a toll of from i to 5 bushels per acre 

 unless control measures are adopted. Experiments 

 seem to show that ploughing under the stubble is 

 the most effective remedy, as wholesale destruction 

 of the insects is thus brought about. It would be 

 necessary to arrange the crop rotation so as to allow 

 the wheat-stubble to be ploughed up, but if this could 

 be done it is estimated that millions of dollars could 

 be saved yearly. 



Parasites such as lice and mites cause considerable 

 loss in the poultry industry by reducing egg-production 

 and injuring the' quantity and quality of the flesh of 

 the birds. A cheap but 'effective remedv is therefore 

 much to be desired, and it is now claimed bv F. C. 

 Bishop and H. P. Wood (Farmers' Bulletin 801, 

 U.S.A. Dept. Agric.) that sodium fluoride fulfils these 

 conditions, and that, if properly used, one application 

 will completely destroy nil the lice present on anv 

 bird. The treatment can be carried out by dusting or 

 by dipping. In the former case pinches of the fluoride 

 are placed among the feathers close to the skin on 

 the parts most frequently attacked; dusting with a 

 shaker is less effective, and also causes more irritatfon 

 to the nose and throat of the operator. In the latter 

 case \-\ oz. of commercial sodium fluoride is dis- 

 solved in a gallon of tepid water, and the birds are 

 then dipped for a few seconds. The lice die more 

 rapidly in this case than when the dry powder is used. 

 It is estimated that the cost of treatment works out 

 to about one farthing per bird, i lb. of sodium fluoride 

 sufficing for about a hundred hens. 



T' 



Investigations of the Upper Air.^ 



HE interesting publications referred to below 

 deal with the investigation of the upper air, 

 the first two being written in German. Dr. Ever- 

 dingen, in Holland, has experienced the same diffi- 

 culty that has occurred in England and elsewhere in 

 carrying on the investigation owing to the scarcity 

 and badness of the necessary materials, on account 

 of which the mean height of the kite and captive- 

 balloon ascents, when compared with that of previous 

 years, was reduced considerably. The two years' 

 reports contain full particulars of each ascent made; 

 they are noteworthy as showing the increasing im- 

 portance of aeroplanes compared with the old method 

 of kites as a means of observation. 



The third publication'. Geophysical Memoirs, 

 No. 14, gives an account of the pilot-balloon ascents 

 made in November and December, 191 1, by Capt. 

 Cave and Mr. J. S. Dines in the Scilly Isles. Plenty 

 of information about the relation of the wind to the 

 surface-pressure gradient up to a few kilometres 

 height over land is available, but similar information 

 about the wind over the sea is very scarce. The 

 expedition to the Scilly Isles was planned and carried 

 out by Capt. Cave expressly to meet this want, and 

 the results, which contain a large and useful amount 

 of information, have at last been published. 



The islands are noted for their fine formation of 

 rock, and they are exposed to the full force of the 

 Atlantic gales; in no part does the surface rise much 

 above the sea-level, and the whole land area is small, 

 thus the influence of the land on the air-currents 

 must also be small. Moreover, except to the south- 

 west, readings of the barometer are available, and 

 hence the isobars on the daily weather charts can be 



1 " Koninklijk Nederlandsch Meteorologisch Institut," No. 106. 

 " Ergebnisse -Verologischer Beohachtungen," pans v. (i 016) and vi (1917). 

 Air Ministrv. Nfeteorologlcal Office. Geophysical Memoits, No. 14 : 

 " Soundings with Pilot-balloons in the Isle« of Scilly." 



NO. 2647, VOL. 105] 



dravvn in the neighbourhood of the islands with fair 

 precision. 



The balloons were mostly followed by two theodo- 

 lites at the ends of a base line of 5260 metres, but 

 on a few occasions, on account of the difficulty of 

 reaching the distant station, only one was used. 'The 

 period covered was from November 22 to Decembers. 

 The weather was mostly rough and stormy with a 

 prevalence of clouds, so that the balloons could seldom 

 be followed to any great height, but the conditions 

 were very favourable for the purpose of the observa- 

 tions. The authors found, as they expected, that 

 the effect of surface-friction is far less at St. Mary's 

 than inland, and they give the loss of velocity at the 

 anemometer head at Scilly as 20 per cent., against 

 35 to 50 per cent, at Ditcham Park. 



The question of the rate of ascent of pilot balloons 

 is considered. The same kind of balloon was used 

 as at Ditcham Park and the same free lift given. 

 The mean rate of ascent was i6o-6 metres per minute. 

 It has been found inland that balloons show a 

 tendency to rise faster in the first half kilometre, 

 but this was not the case at Scilly. The rate of 

 ascent varied considerably from minute to minute, 

 but no systematic difference was found, and hence 

 the authors conclude that the general results obtained 

 from single theodolites may be looked upon as quite 

 trustworthy 



The last section deals with the type and height of 

 the clouds prevalent during each ascent, and some 

 evidence was found of the motion of the upper clouds 

 away from the centre of the depression which 

 dominated the weather at the time. 



The whole memoir is very interesting and should be- 

 read by every student of meteorology. 



Bionomics of Qlossina palpalis. 



NO. XVII. of the Reports of the Sleeping Sickness 

 Commission of the Royal Society (H.M. 

 Stationery Office, price 45. net), which has recently 

 been issued, includes the third, fourth, and fifth 

 reports on the bionomics of Glossina palpalis on Lake 

 Victoria by Dr. G. D. Hale Carpenter, of the Uganda 

 Medical Service. 



Interesting descriptions are given of the natural 

 features and of the fauna and flora of the thirty- 

 six islands visited. These should be consulted in the 

 original by those interested. F"rom a study of the 

 conditions prevailing in these islands it was deduced 

 that the conditions for the prevalence of fly above 

 the average are (i) suitable breeding-grounds, viz. 

 dry sand or gravel ridges representing old lake-shore 

 levels ; (2) abundant shade combined with open spaces 

 to permit of the movements of the fly ; and (3) absence 

 of large spiders (PNephila). 



The characters of a suitable breeding-ground are 

 the following : (i) Loose soil, (2) dry soil, (3) well- 

 ventilated soil, (4) adequate shade, and (5) within 

 20-30 yards of water. Further research will probably 

 enable us to define these conditions still more precisely 

 and to decide whether they, as one would expect, are 

 also the optimum for the development of ounae. 



The practical suggestion is made that fly may be 

 controlled by constructing artificial shelters with the 

 characters above defined which would be attractive 

 to the fly as breeding-grounds, and where the pupa& 

 would be regularly collected and destroyed. ^ It might 

 be possible to add some chemical fo the soil in these 

 shelters which would obviate the necessity of collec- 

 tion and destruction. The author has established the 

 fact that flies pupate in these shelters. 



