1 84 



NATURE 



[December 8, 19 lo 



are seeking, I believe, without exception, to advance the 

 material interests of those whom they represent. The 

 claims which you put forward on behalf of experimental 

 research would be wholly unselfish. They would be for 

 work in the common interest, in the interest of mankind. 

 In the report for the year there is a very long list of work 

 <ione in different departments of scientific research with 

 small sums like lol. or so given out of your small Govern- 

 ment grant to meet expenses. It is a list capable of in- 

 ■definite expansion, and indicates work that might be done 

 on a larger and more fruitful scale. Undertakings like 

 the Research Commission to Uganda may well return 

 their cost a hundred-fold, and I venture to suggest that an 

 appeal should be made to those in charge of the Develop- 

 ment Fund to give a wider scope to your disinterested and 

 most beneficent activities." 



COTTON GROWING WITHIN THE BRITISH 

 EMPIRE. 



'T'HE British Cotton Growing Association was inaugu- 

 "*■ rated in 1902 with the object of extending the culti- 

 'vation of cotton throughout parts of the British Empire 

 where conditions should prove suitable. During the eight 

 years that have elapsed, valuable information has been 

 acquired by means of pioneering expeditions and experi- 

 mental cultivation in more remote parts of the Empire 

 and from the results yielded by private undertakings that 

 have been liberally assisted with technical advice and 

 financial means. As it was announced a year ago, the 

 inquiry stage is practically completed, and it has been 

 <lecided to concentrate the main efforts of the association 

 >on the work in Nigeria, Uganda, Nyasaland, and the 

 West Indies. The present state and future outlook of the 

 cotton industry are therefore opportunely summarised in 

 the address delivered by Mr. J. H. Reed before the Royal 

 'Geographical Society on Monday, December 5. 



The principal supply of raw material from the United 

 States of America has increased during the last quarter 

 of a century from seven to thirteen million bales per 

 annum ; the output of India may reach a total of five 

 million bales, but most of it is short-stapled, and Egypt 

 supplies somewhat more than a million bales. Against 

 this has to be placed the demand for cotton, which in this 

 country has remained nearly stationary, at a total of three 

 million bales, while the United States of America now 

 require nearly five million bales, and the countries of 

 Europe absorb six million bales. With regard to other 

 -sources of supply, the class of cotton grown in the West 

 Indies is of good quality, but owing to . the limited area 

 the amount produced can never be large, so that the most 

 hopeful fields for the labours of the association lie in 

 West and Central Africa. The colony of Lagos bids fair 

 to produce an appreciable quantity of cotton ; the extension 

 of the industry in Nyasaland, where a superior type of 

 upland is a prominent variety, is distinctly encouraging, 

 and the late High Commissioner of Uganda has reported 

 ilfKjn the favourable climate and conditions, as well as the 

 ■eagerness of the natives in that Protectorate for taking up 

 ■cotton cultivation. In the Sudan there are large areas of 

 suitable land near the junctions of the Atbara and the 

 Blue Nile with the main stream, in the province of Berber, 

 and on the plains between the converging courses of the 

 Blue and White Nile. Of the prospects in Rhodesia it is 

 too early to pronounce a definite opinion, but the experi- 

 mental work gives promise of the possibility of a native 

 industry being developed under European guidance. 



PESTS OF FRUIT TREES. 



A 



FRUIT-GROWERS' conference was held, in conjunc- 

 tion with the National Fruit-growers' Federation, at 

 Wye College, Kent, on December 2. Nearly six hundred 

 persons, mostly fruit-growers in Kent, attended. The 

 papers of scientific interest were read by Mr. F. V. Theo- 

 bald, vice-principal and entomologist at the college, and 

 by Mr. E. S. Salmon, mycologist. 



Mr. Theobald dealt with the damage done to fruit trees 

 by Thrips. At least three species of Thrips damage fruit 

 trees and bushes, the commonest, apparently, being 

 Euthrips pyri, Daniel. This species is found on apple, 



NO. 2145, VOL. 85] 



pear, plum, raspberry, loganberry, and strawberry. The 

 winged adult females first enter the opening buds, and 

 then by means of their conical mouths so lacerate the 

 young tissue that the buds die soon after opening. Leaves 

 and blossoms are also attacked. The ova are laid in slits 

 cut by the female in the young leaves and strigs. The 

 pale, wingless larvaj attack the young fruitlets, which 

 either crack and drop off prematurely, or, if less injury 

 is done on somewhat larger fruitlets, the abrasions lead 

 to the formation of areas or scars, which disfigure or even 

 entirely ruin the fruit. The larvae when mature enter the 

 soil, and there produce a pupal stage with long wing buds, 

 and the winged Thrips appear again. The winter is passed 

 in the larval stage in the earth. Treatment with soil 

 fungicides appears to be the only practicable method of 

 dealing with this fruit pest. 



Mr. E. S. Salmon dealt with the epidemic outbreak of 

 Eutypella prunastri, which during the past fev/ years has 

 destroyed thousands of young fruit trees in certain districts 

 in Kent, Herefordshire, and Worcestershire. In one casr 

 near Canterbury 1200 " Victoria " plums, 300 " Czars,'" 

 and 50 " Monarchs " were attacked and killed. Th<' 

 variety of plum called " Rivers Early Prolific " appears t< 

 possess powers of resistance to Eutypella. Young appl- 

 and cherry trees have also been destroyed by this disease. 



The life-history of the apple " scab " fungus (Venturia 

 inaequalis) was dealt with, and instances were given which 

 showed that this disease can be successfully prevented by 

 the use of the fungicide known as " Bordeaux mixture." 

 The statement sometimes made by growers that the 

 " scab " fungus can infect and spread on stored apples is 

 due to an error of identification. Recent investigations 

 made by Mr. Salmon show that we have in this country 

 a species of Leptothyrium, not hitherto reported, which 

 attacks apples both on the tree and in the fruit-room, and 

 forms sooty-looking spots on them. It is probably the 

 species L. pomi, well known in America as the cause of 

 the " sooty blotch " and " fly speck " diseases. 



Evidence was adduced as to the different degrees of 

 susceptibility to injurv from Bordeaux mixture shown by 

 different varieties of English apples. 



THE DISCOVERY OF NEPTUNE. 



LEVERRIER'S LETTER TO GALLE. 



"V^HILE so much has been written about the dramatic 



* discovery of the outermost known planet, it is 

 strange that until quite recently the full text of the letter 

 in which Leverrier announced to Galle the results of his 

 wonderful investigations appears not to have been 

 published. 



A copy of this historic document was communicated by 

 its recipient to Dr. See about five years ago, for use in a 

 work on the planetary system which the latter was then 

 preparing. But the death of Galle in July last has 

 prompted Dr. See to anticipate the issue of his work by 

 publishing the letter by itself in No. 8, vol. xviii., of 

 Popular Astronomy (October, p. 475). The ostensible 

 reason for writing to Galle was to acknowledge the receipt 

 of the memoir which the latter had prepared, and in 

 which he had reduced and critically discussed Roemer's 

 synopsis of three days' work, which alone escaped the 

 conflagration of 1728, under the title " O. Roemer's 

 Triduum Observatorium Astronomicarum a. 1706 Institu- 

 torum " (Berlin, 1845). The letter runs as follows : — 



" Paris, le 18 septembre 1846. 

 " Monsieur 



"J'ai lu avec beaucoup d'int^ret et d'attention la reduc- 

 tion des^ observations de Roemer, dont Vous avez bien 

 voulu m'envoyer un exemplaire. La parfaite lucidity de 

 Vos explications, la complete rigueur des r^sultats que Vous 

 nous donnez, sont au niveau de ce que nous devions 

 attendre d'un aussi habile astronome._ Plus tard, _ Mon- 

 sieur, je Vous demanderai la permission de revenir sur 

 plusieurs points qui m'ont int^resse, et en particulier sur 

 les observations de Mercure qui y sont renferm^es. 

 .Aujourd'hui, je voudrais obtenir de i'infatigable observa- 

 teur qu'il voulut bien consacrer quelques instants a 

 I'examen d'une region du Ciel, ou il peut rester une 

 Plan^te k d^couvrir. C'est la theorie d'Uranus qui m a 



