AruiL 8, K.09] 



NATURE 



171 



osieriagi, new to this country, and large numbers of the 

 rare Sclcrostoma hypostomum. 



Exigencies of space forbid the mention of other con- 

 tributions. 



G. 3. — A branch of seeded hops produced 

 identical conditions as those shown in Fig. 

 supplied to the " burr." 



bine and unde 

 :cept that pollen wa 



The letterpress and plates are alike excellent, and, as 

 a year's record of all that is best in scientific agriculture, 

 the Journal of the South-Eastern Agricultural College 

 should find a place on many bookshelves. 



C. A. E. 



T//E ROYAL PRUSSIAN AERONAUTICAL 

 OBS£RVA TORY'S AEROLOCICAL EXPE- 

 DITION TO TROPICAL EAST AFRICA. 

 'PHF, Royal Prussian Aeronautical Observatory, Linden- 

 berg, supported by the active interest of some " friends 

 of science," sent out in June, 1908, an aerological expedi- 

 tion to tropical East Africa under the direction of Prof. 

 Berson, first observer at Lindenberg, accompanied by Dr. 

 Elias, formerly assistant, and Mr. Mund, balloon super- 

 intendent of the observatory. At the end of December last 

 they returned safely, and in possession of a good amount 

 of interesting data. 



In consideration of the proximity of the region explored 

 to British possessions in East Africa, and also in recogni- 

 tion of the help and protection given to our work by the 

 English authorities, I asked Prof. Berson to write a special 

 report for Natl're, believing that there are British readers 

 who take interest in our work. 



1 am therefore glad to offer the following account of the 

 work by Prof. Berson. R. Assm.ann. 



Director of the Royal Prussian Aeronautical 

 Observatory, Lindenberg. 



Much good work has been done lately in the explora- 

 tion of the upper atmosphere in the region of the trade 

 winds, more particularly the Atlantic trades, where men 

 of science of Oerinany, the United States, and France 

 have been making investigations, trying above all to 



NO. 2058, VOL. 80] 



elucidate the very important question of the anti-trade. 

 But in the Indian Ocean and the adjacent regions, the 

 realm of the most powerful and persistent monsoonic 

 system of the globe, with the exception of a few ascents 

 from the German ship Planet, carried out in the southern 

 and eastern portions of the ocean, only the Indian meteor- 

 ologists, Mr. Walker and Mr. Field, had applied the new 

 aerological methods for the study of the monsoon pheno- 

 mena, the work in the south-west monsoon proving 

 especially difHcult on account of the stormy and rainy 

 character of the weather prevailing during its sway. 



Very naturally the idea occurred to try similar explora- 

 tions on the east African coast and the waters washing it, 

 the region lying at the starting point or (in the case of the 

 Indian " winter monsoon ") at the extreme limit of these 

 peculiar wind-systems. It might be expected that there- 

 would be less difficulty to be encountered here than m 

 India proper, especially if the work were carried out on 

 the water, where self-registering balloons might be found' 

 easier, by means of a small steamer chartered for the 

 purpose, and the wind, if too weak or too strong for kite 

 ascents, increased or lessened by the motion of the vessel. 



This plan once conceived, it occurred to us that some 

 600 miles further inland there was situated a vast sheet of 

 water — the Victoria Nyanza — on the surface of which all 

 the above-named advantages might be met for balloon as 

 well as for kite work, thus affording the possibility of 

 efficient and fruitful aiirological research in the heart of 

 a tropical continent, even in the middle of the equatorial 

 belt, a unique spot of similar convenience to be found on 

 the surface of the globe. 



The Royal Prussian Aeronautical Observatory, the well- 

 known creation of Prof. Assmann, took the matter in 

 hand, and after having overcome a rather lengthy series 

 of difficulties — above ail, naturally enough, of a financial 

 character— chiefly by the persistence of Prof, .■\ssrnann and 

 the generosity of a few wealthy friends of scientific work 

 we succeeded in carrying out our plan, at least in the 

 leading features. This had in itself a double bearing. 

 The first item consisted in an investigation of the mon- 

 soons, more particularly of the conditions of their change 

 in the north-hemispheric autumn, and the intervening land 

 and sea breezes, on the coast of British and German East 

 ."Kfrica, as well as on the neighbouring sea (as a matter of 

 fact, the work was carried far beyond the limits of the 

 monsoons, down to the tropic of Capricorn). The other 

 point was the " studv of the tropical, or, more exactly 

 speaking, the equatorial continent "—in contrast to the 

 ocean of the same latitudes — from the aiirological point of 

 view, over the Lake Victoria, implying the research of the 

 vertical distribution of temperature, the question of the 

 " upper inversion," the studv of the winds prevailing in the 

 different strata, and, in addition, a comparative investiga- 

 tion of the land and sea breezes of the lake in analogy to 

 those on the coast of the ocean. 



For scientific and practical reasons, though, the experi- 

 ments had to be executed in the inverse order ; we began 

 by the ascents on the large " inland sea of Central Africa," 

 and wound up by research on the ocean. 



The writer, as leader of the expedition, accompanied 

 by Dr. Elias, and a technical assistant, left Europe 

 iri the middle of June, and managed, after some little 

 delay at Mombasa and Nakuru, to arrive, viA^ Uganda 

 Railway and the lake, with all our cargo of windlasses, 

 kites, balloons, chemicals, instruments, and personal eqiiip- 

 ment', on July 24 at Shirati, in German East Africa, 

 situated on the east coast of the Nyanza, in 1° 7' S. lat. 



That all the difficulties which, of course, did not faif 

 to arise could be overcome with so little loss of time is 

 to a large extent due to the extreme courtesy, or in many 

 cases even most helpful assistance, with which the ex- 

 pedition- met everywhere in British East Africa. For this 

 the observntory is largelv indebted to Dr. Shaw, the 

 director of the Meteorological Office, to the Coloniaf 

 Office and to all the authorities, Imperial as well as local, 

 in British East Africa and Uganda. We beg to express 

 our feelings of sincere gratitude to nil of them, most par- 

 ticularly to Dr. Shaw and to the officials of the Ugand.t 

 Rflilw.iv. the custom .Tnd nort officers in all those traces, 

 and the officers of the steamers plying on Lake Victoria. 



Owing to this loyal help we succeeded in securing a 



