THE PRESENT STANJJPOINT OF GEOGRAPHY. . 413 



An immense mass of work remains to be done to enable us to liave 

 even a rough and general knowledge of the ocean depths. Additional 

 lines of soundings are needed in all directions, especially in the 

 Southern Ocean and in the central Pacific, to bring out their general 

 contignration. We now have a rough idea of the areas of greatest 

 depths, the greatest of all having been obtained off" the coast of Japan 

 by the Tmcarora in 4,655 fathoms; but the soundings of the Challenger 

 between St. Thomas and Bernmda and of the Eijeria in the Pacific come 

 very near to it. The discovery of the very greatest ocean depth will be 

 most interesting, but it would be still more so to discover and map the 

 submarine ranges and peaks to within, say, 500 ftithoms of the surface. 

 I remember that when the Valorous ran a line of soundings across the 

 North Atlantic in August, 1875, we got 1,860 fathoms on one day, 1,450 

 on the next, and only 600 on the next, bringing up pieces of black vol- 

 canic stone. On the two following days the depth increased to 1,250 

 and 1,485 fathoms. Here there was clearly either a volcanic peak or a 

 ridge; and wherever these are known to occur 1 think that it would be 

 very desirable to explore the surrounding ocean bed and ascertain 

 their extent and character. We want also the establishment of a more 

 complete study of the system of ocean currents by a very extensive 

 use of floats adapted to swim at various depths, and also a fuller inves- 

 tigation of the temperature and density of the water surrounding the 

 shores of all the continents. The work hitherto done in the North Sea 

 and the neighboring Atlantic is practically confined to the summer 

 months, and a detailed examination at all seasons is needed. Such 

 work is now being done under the auspices of Profs. Petterssen, of 

 Sweden, and Mohn, of Christiania, Kriimmel, of Kiel, and the fishery 

 board of Scotland. We also require a determination of the isotherms 

 and isobars on land and sea at all seasons, which will primarily 

 involve prolonged observations in the South Polar region, and a more 

 complete knowledge of the variation of atmospheric pressure with 

 height, and its independent variation in different horizontal planes. 

 Such an investigation embraces the whole question of the use of the 

 barometer or boiling-point thermometer in measuring heights. 



This will conclude my enumeration of the geographical desiderata in 

 the field. It is a long and formidable list, affording work for many 

 decades of years to come. But-many of my associates know very well, 

 and the rest must now clearly understand, that it is by no means an 

 exhaustive list, but only such an enumeration as our limited time will 

 admit of our making, merely a rough general survey of the work in the 

 field that remains to be done. 



The work of explorers is co ordinated and rendered useful in many 

 ways by geographical students, whose valuable labors desire equal 

 attention and encouragement. There are many geographical problems 

 Miiich must be solved as well by the examination and intercomparison 

 of the work of numerous explorers in different regions as by the care- 



