TRANSACTIONS OF THE SECTIONS. 137 



latitude, taking the Sandwich and Society Islands by the way, and afterwards turned 

 east across the remaining half of the Pacific, reaching Valparaiso at the end of 

 November 1875. The Straits of Magellan were traversed during the first days of thfe 

 year 1876, and the expedition was at Monte Video on the 25th of February, at the 

 Cape- Verde Islands on the 20th of April, and at Spithead on the 24th of May 1870. 

 By this memorable expedition, Dr. Carpenter's views of the vertical circulation 

 of the ocean were substantially confirmed. It was found that the old idea of a 

 uniform deep-sea temperature of 39° was an error, which had been caused by the 

 derangement of the readings of the old unguarded thermometers under the pressure 

 of the water of the deep sea, and that a temperature of 32° prevails at deep ocean 

 bottoms, even at the equator, the cold there being due to a constant underflow of 

 dense water from the Polar seas towards the equator. But wherever the deep 

 basins are protected from the cold lower currents by comparatively elevated ridges 

 of rock, the deep soundings give warm water in the place of cold. This was 

 remarkably instanced in the Gulf of Mexico, and in the ridge-protected basins of 

 the Banda, Celebes, and Sulu seas. The temperature was found to be 50° at 

 1800 fathoms in the Sulu Sea, although in the neighbouring open China Sea it 

 was 37° at only 900 fathoms. In the Celebes Sea the temperature was 384° at 

 2007 fathoms. _ • < 



In the Atlantic the very interesting fact has been determined by the ' Challenger' 

 soundings that the basin of the ocean is divided into two subordinate troughs by a 

 submarine ridge running from south to north through the Dolphin Rise and the 

 Azores, to the shallow water which bounds the Atlantic to the north. The average 

 depth of the Atlantic seems to be within 2640 fathoms, or three miles. The 

 deepest sounding in the Atlantic was in a depression lying 100 miles north of St. 

 Thomas, where the bottom was reached at 3800 fathoms, or four and a quarter 

 miles. The deepest sounding in the Pacific was midway between New Guinea and 

 Japan, in 11° N. and 143° E., where the bottom was reached at a depth of 4475 

 fathoms, or 453 feet more than five miles. Very near to this the temperature of 

 the deep sea was found to be 33 0, 9. In this deepest sounding one of the thermo- 

 meters was broken, but red clay was brought up from the bottom. Throughout 

 the long examination of the ocean depths by the ' Challenger/ the conclusion was 

 amply confirmed that there is animal life at all depths. 



Maritime meterology, which has resolved itself into a distinct subject of investi- 

 gation, and is being conducted in this country under the direction of Mr. Robert H. 

 Scott, F.R.S., and the Meteorological Committee, will be productive of useful and 

 practical service in navigation. International Conferences were organized at 

 Brussels in 1859, when suggestions for a uniform system of meteorological observa- 

 tions at sea were adopted for observance by the navies and mercantile marine of all 

 nations. The patient and laborious collating from the returns and logs of ships 

 made by Admiral Fitzroy have produced those descriptive ' Tract Charts ' and 

 Pilot Charts which tend to curtail the length of voyages and avoid disaster ; 

 and under Admiral Richards, Hydrographer of the Admiralty in 1868 and 1872, 

 there was published a work containing a set of Charts showing the winds and 

 currents of the oceans on the surface of the globe, which has been highly valued 

 as a work of reference by the navigator. A journal is published by the Meteoro- 

 logical Committee, which elaborately discusses all the materials collected on the 

 subject of ocean meteorology. 



We must now direct our attention to the gTeat continent of Africa, where the 

 obstacles to be overcome by the traveller are very different from those enumerated 

 in the Arctic wastes, but are scarcely less terrible to encounter. Again referring 

 to the year 1841, speculations were then rife as to the sources of the Nile, the 

 region of tropical lakes was unexplored, and the whole river-system imperfectly 

 known. In place of desert in the interior high lands with fertility and a climate suited 

 to Europeans has been found. To enter into the marvellous extent of work accom- 

 plished by all the distinguished travellers, from the early days of Livingstone 

 to the last feat of Cameron, could not be compressed into this Address. 



In 1845 we find Mr. Murchison, in one of his early addresses, observe, " Indeed 

 it woidd be difficult to instance any part of this world whose streams have given 



1877. 11 



