TKANSACTIONS OF THE SECTIONS. 117 



feet. The lake is tlieii 100 miles long and sixty or seventy broad, and tlio water is 

 not liberated until the end of the rainy season. The author exhibited to the Section 

 a large series of photographic views, copies of inscriptions, and ground-plans. 



Notes on the Physical Geocjrapliij of tlie Lotver Indus. 

 By Col. Tkemenheeke, B.E. 

 The immense plain of Siud presents a remarlvable peculiarity throughout— 1, in 

 the entire absence of channels for natural drainage ; 2, in its almost uniform slope, 

 both towards the sea and away from the river banks ; .3, in its mineral character. 

 The slope of the valley in a direct line to the sea, 330 miles, is 9-3 inches per mile, 

 and the lateral slopes on either side of the river are in many parts quite as much. 

 The liver, in fact, passes along a ridge. For 540 miles the surface slope of the Indus 

 during the inundation is 57 inches per mile. The soil consists entirely of a very 

 fine siliceous deposit mixed with argillaceous matter and mica ; not a grain of sand 

 is to be foimd as large as a pin's head. The solid matter in the water of the Indus 

 during its immdation amoimts to 43'G parts in 10,000 by weight. The mean dis- 

 charge of water being 200,000 cubic feet, and the mean' solid matter 25 in 10,000, 

 it results that 21 7 J millions of cubic yards of solid matter are carried annually to the 

 sea, which is suiRcient to cover seventy square miles of area with deposit one yard 

 in thickness. The author investigated the various old channels of the river, and 

 came to the conclusion that the stream has gi-adually worked to the westward. lie 

 also concluded that the larger the body of water in rivers flowing through such 

 plains, and the less the surface-slope of the plain, the more direct will be the course 

 of the liver ; and, on the contrary, the sharpness of the bends of a large river will 

 indicate the existence of a considerable slope. The longer, therefore, a ri^er becomes 

 by extending its delta into the sea, the gxeater tendency will there be to assume a 

 more direct course. The author also carefully examined the delta of the Indus, and 

 gave in detail the result of his observations. 



On the Progress of the Pusso- American TeleyrapJi Expedition via Behring^s 



Straits. By F. Whymper, F.P.G.S. 

 The author, after exploring parts of Vancouver's Island, attached himself, in the 

 capacity of artist, to the expedition which proceeded last year from San Francisco 

 to survey the line for the proposed Siberian and American telegraph. There exists 

 already a line to New Westminster, Fraser Eiver, from which point the new line 

 is to commence. Five vessels started with the exploring parties in July 1805 ; one 

 of them proceeded to Plover Bay, in Siberia, whilst the others were to meet at 

 Sitka, in JRussian-America. The vessel in which Mr. Whimper sailed proceeded 

 through the Aleutian Archipelago to Norton Sound, in Behring Sea, and thence 

 crossed to the river Anadyr, in Siljeria. .\ small screw steamer, brought on board 

 one of the larger vessels, took an important section of the party, under Major 

 Kennicott, to explore the Kirchpak River. The average depth of Behring's Straits 

 between 64° and 60° N. lat. did not exceed 20 fathoms. The author returned to 

 San Francisco in November, the fleet having deposited the various exploring par- 

 ties in their winter quarters on the coasts of America and Siberia. The preparations 

 for 1806 were on a more extended scale ; and by the end of the year it was supposed 

 that about 1500 miles of the line would be laid northward of Fraser lUver. 



ECONOMIC SCIENCE AND STATISTICS. 



Address ly Professor James E. Thoeold Eogees, M.A., President of the Section. 



The Presidents of the various Sections among which the scientific labours of the 

 British Association are distributed have, beyond the general conduct of their 

 several departments, the obvious and important duty of dwelling in their introduc- 

 toi-y address on the progress made during the past year in the special science with 

 which they are for the time being identified. Nor is there ever wanting abundant 



