4 
THE VOYAGE OF H.M.S. CHALLENGER. 
jire left at the bottom of the sea, while the tube containing a specimen of the deposit is 
hauled to the surface and on board ship. During the first 
months of the cruise the diameter of the tube was not more 
than 1 inch,^ but this was replaced by one having a diameter 
of 2^ inches,^ and latterly the tube was made to project fully 
18 inches^ below the weights. When there was reason to 
suppose that the bottom would be a tenacious clay, no 
butterfiy valve was used at the lower end of the tube, as 
this valve is a great impediment to the entrance of the 
deposit into the tube. In these cases the tube sometimes 
sank 1 8 inches or 2 feet * into the clay, and brought up a 
section to that depth and over a quart ® bottle fuU of the clay. 
It not being always possible to know beforehand the nature 
of the bottom, it was found by experience best to have the 
tube always fitted with the butterfly valve when sounding, 
for a Globigerina Ooze or other less tenacious deposit was not 
retained in the tube without the valve. To facilitate collect- 
ing the mud or other deposit brought up by the tube, the 
lower half was made to unscrew, and this was then taken into 
the laboratory, the butterfly valve removed, and the roll of 
mud or other deposit taken out at the upper end, or allowed 
to slip out by its own weight, on jerking or on striking it 
gently on the table. The arrangement, colour, and general 
appearance of the difierent layers, if any, were then carefully 
noted. Even when the whole of a more or less granular 
deposit appeared to have been wholly washed out of the tube 
on its way up through the water, still a small quantity of the 
deposit or a few shells or stones would usually be found 
inside behind the valves. The method of sounding with these 
machines is very satisfactory from the point of view of the 
study of Deep-Sea Deposits, for the largest specimens of the 
deposit arc thus ol)taincd ; the method of sounding with 
wire, now chiefly employed, where the weights and tubes are 
verj’ much less, is le.ss satisfactory in this respect. 
Buchanan’s combined sounding tube and water-bottle, as 
used by Mr. Buchanan with success on board the telegraph 
ships, is represented in Figs. 7, 8, 9, and 10, and has the 
advantage of utilising the weights in pushing the tube into the ground, with the 
j—# 
Flo. 7.- Bofhjin*n'i CorotiiDerl Sotui4- 
lug Tab* ud W«ter-nottle. 
• 25*4 mm. 
* 63'7 mm. 
* I.*) ? ccntimetrc«. 
< Cl centimetres. 
^ litres. 
