306 



SCIENCE 



[N. S. Vol. XXXI. No. 791 



deal in any way with the science of the earth's 

 atmosphere; a book which has laid the whole 

 scientific world under a debt of gratitude to 

 its author, impossible to overestimate. 



E. DeC. Ward 



J 



SPECIAL ARTICLES 



EARTH MOVEMENTS AT LAKE VICTORU DT 

 CENTRAL EAST AFRICA 



The profound significance for Central East 

 Africa of the fall of Omdurman in 1898 has 

 been strikingly brought out by subsequent 

 scientific publications of the Egyptian Survey 

 Department. Captain H. G. Lyons, late the 

 eminent director general of that department, 

 and now occupying the newly established chair 

 of geography at the University of Glasgow, 

 published in 1906 an extended monograph 

 upon the Nile Eiver and basin.^ This volume, 

 which is issued by the finance ministry, com- 

 pels admiration as much by its exhaustiveness 

 as by its orderly arrangement and lucid pre- 

 sentation of the facts. Through setting forth 

 in a well-digested summary the scientific re- 

 sults secured by early and late explorers and 

 scientific travelers, and by including a full 

 bibliography of the geography and geology of 

 the district, the work has been made authori- 

 tative and indispensable. 



Those who have not already interested 

 themselves in the region will be surprised to 

 learn how many observing stations supplied 

 with water gauges, have been established upon 

 the Upper Nile and its tributaries, and of the 

 almost continuous series of careful gauge 

 readings extending over a full decade. 



The very interesting conclusions on the 

 basis of these readings, which were fore- 

 shadowed in the monograph above cited, are 

 contained in a very recent report of the Sur- 

 vey Department." The conclusion to which 

 Captain Lyons is forced is that the gauges 



' " The Physiography of the Nile River and its 

 Basin," Cairo, National Printing Department, 

 1906, pp. 411 and numerous maps. 



' " The Rains of the Nile Basin and the Nile 

 Flood of 1908," by Captain H. G. Lyons, F.R.S., 

 Survey Department Paper No. 14, Cairo, 1909, 

 pp. 69, pis. 8. 



have registered oscillations of level of the 

 ground about Lake Victoria. Upon the north- 

 ern and northeastern shores of this lake three 

 gauges were established — one at Entebbe on 

 the northwest shore, another at Jinja on the 

 north shore where the Nile leaves the lake, and 

 one at the head at Kavirondo Gulf near the 

 railway terminus on the northeast shore. Al- 

 though all three gauges have been moved since 

 they were first established, and though there 

 are some gaps in the records, yet in the main 

 it is true that daily gauge readings are avail- 

 able from three widely separated stations since 

 September 30, 1898. 



Study of the monthly averages of these 

 readings has shown with much probability 

 that in October, 1898, a sinking of the land at 

 Entebbe began and continued during 1899. 

 It was most marked during August and Oc- 

 tober of that year. At the end of ' 1900 

 and during the early months of 1901, a 

 slight elevation seems to have occurred, 

 though in May and June following a renewed 

 sinking took place. This movement on the 

 northwest shore of the lake seems not to have 

 been participated in by the land farther to the 

 eastward. These local movements, extending 

 as they do over several months, can not be ex- 

 plained by wind effects. 



From November, 1901, to February, 1902, 

 the Jinja gauge curve was on the whole rising, 

 while those at Entebbe and Kisumu were fall- 

 ing steadily. Again in December, 1902, the 

 Jinja curve was steady, while those of En- 

 tebbe and Kisumu were rising, but in Feb- 

 ruary, 1903, the case was reversed. Subse- 

 quent to these later dates the gauges have 

 shown no noticeable discrepancies which could 

 be attributed to a recurrence of oscillations 

 of level until in 1908, when at Jinja the lake 

 level fell 14 inches between February 5 and 

 19, the change of level at each of the other two 

 stations being only an inch and a half. 



To quote Captain Lyons, aU the available 

 information " points to the frequent and re- 

 cent differential movement of great blocks of 

 the country." Following Herrmann he states : 



The movements of upheaval have acted along 

 NNE-SSW directions, and the intensity seems to 



