GEOGRAPHY. 475 



large portion of Krakatoa island, causing' immense waves, which, after 

 retreating, rolled in on both sides of the straits, destroying towns and 

 villages and drowning at least 100,000 people. Whole districts were 

 covered with pumice and ashes, and the island of Krakatoa was reduced 

 to a fraction of its original size — water a thousand feet deep being found 

 where the greatest activity of the volcano was displayed. The chan- 

 nels of navigation were very much changed, and surveys have been car- 

 ried on since the outburst to lay down the changed depths in the differ- 

 ent passages. At the time of the great explosion two enormous waves 

 were set in motion, and the same afternoon were registered on the tide 

 gauges at Mauritius, the Seychelles in South Africa, and at some of the 

 Pacific islands, and there is evidence that, proceeding onward, these 

 waves crossed each other on the antipodes of Krakatoa, thus returning 

 to the place of their origin no less than four times before the equilibrium 

 of the sea was restored. Atmospheric waves were also sent round the 

 globe by this terrific disturbance at very nearly the same velocity as 

 that of sound, while such masses of dust and ashes were driven into 

 the upper regions of the air as to cause unusually lurid skies and other 

 remarkable atmospheric phenomena for some months all over the world. 

 A committee of the Royal Society has been appointed to fully investi- 

 gate all the physical phenomena connected with the subject, and their 

 report will present an accurate account and examination of the effects 

 of volcanic eruptions. 



In the last report of the operations of the great Trigonometrical Sur- 

 vey of India, General J. T. Walker, R. E., the superintendent, states 

 that the principal triaugulatiou of all India on the lines originally 

 marked out by Colonel Everest has now been completed. General 

 Walker gives a brief review of the operations from 1800 to the present 

 day. The details of the topographical surveys have been diligently 

 carried on, and many maps have been published during the past year, 

 but the chief geographical interest attaches to the trans Himalayan 

 explorations by native travelers. The regions explored as far as is 

 made known were the water-shed of the Upper Oxus, and its chief trib- 

 utaries, a large area in Great Tibet explored by a traveler known as 



A K , who has recently returned to Calcutta after an absence of 



four years, and who has been able to settle a vexed question as to the 

 affluents of the Irawadi and the Brahmapootra. In addition to the re- 

 ports of these and other native officers, the narratives of English officers 

 included in this report contain a very large amount of information, es- 

 pecially regarding little known portions of British Burinah. 



In an address to the Geographical Section of the British Association at 

 Southport, in September, 1883, Lieutenant-Colonel God win- Austen gave 

 a description of the general structure of the mountain ranges popularly 

 known as the Himalayas, especially dwelling on the indications of gla- 

 cial action as compared with similar markings in the Alps. Colonel 

 Godwin-Austen indorsed Sir H. Strachey's conception of the general 



