TEE WORK OF THE "ALBATROSS" 243 



earth. The four or five thousand separate soundings, made by the 

 Albatross during the past twenty-seven years, indicate a long and per- 

 sistent bombardment of the ocean depths. 



Clamped to the sounding line, a few feet above the bottom specimen 

 cup, is a second brass cylinder used to bring up a sample of the water 

 from the bottom to be tested for its specific gravity. The water bottle 

 is sent down with its valves open, but on being hauled up, the reversed 

 motion of the water against the blades of a propeller-like wheel tightly 

 screws up the valves, and a pint or so of water from the very bottom is 

 brought up through a depth of several hundreds or even thousands of 

 fathoms, 



A thermometer in a brass case is also clamped to the sounding line 

 above the water bottle. This is sent down right end up, but on starting 

 back to the surface, a water wheel, similar to that used to close the 

 valves of the water bottle, unscrews a catch holding one end of the 

 thermometer, while the other end is fastened by a loose pin, thus up- 

 setting the instrument, which is now brought to the surface with the 

 mercury in the same position as when it left the bottom. At the same 

 time that the sounding is being made, a specimen of the water at the 

 surface is taken, which is also tested for its temperature and density for 

 comparison with the density of the bottom specimen. 



For depths under a hundred fathoms, a hand sounding machine with 

 a light cotton line is used, to which the usual instruments may be 

 attached, unless the navigator wishes merely to determine his position 

 with respect to some shoal. In this case a long weight with a hollow in 

 its end filled with tallow is used, and enough sand or mud sticks to the 

 tallow to indicate the character of the bottom. 



On account of cross currents below the surface and on account of 

 the drifting of the ship with the surface currents or the wind, taking a 

 sounding is often extremely difficult, especially if at any great depth, 

 when it requires that the ship be held in one position for several hours. 

 Not infrequently, in spite of the greatest care, the sounding line goes 

 down obliquely instead of perpendicularly and comes across the edge of 

 the rudder or a propeller blade, or a kink is thrown into the line, which 

 causes the wire to snap off at once, and the whole set of instruments is 

 lost. The deepest sounding made from the Albatross, while on her 

 Philippine cruise, was in the Sulu Sea at a depth of over 2,200 fathoms. 

 Several successful dredge hauls have been made at depths of over a 

 thousand fathoms, but most of the work has been done in water less 

 than five hundred fathoms deep among the depressions and along the 

 edges of the partially submerged plateau which forms the Philippine 

 archipelago. 



The dredging apparatus carried by the Albatross is of two sorts, 

 the dredges which are dragged over the bottom and the intermediate 

 nets which are trawled between the surface and the bottom. Of the 



