of Edinburgh, Session 1885 - 86 . 
541 
arrangement. Their inadequacy for the work led to the construction 
of entirely novel forms for the “ Challenger.”* The stop-cock 
water-bottle is a cylinder with a large stop-cock at each end, the 
levers of which are connected by an outside bar carrying a plate so 
arranged that it becomes horizontal when the line is hauled in, closes 
the stop-cocks by its resistance, then falls and hangs freely. 
In the water-bottles already described water traverses the ap- 
paratus while it is being lowered, and as the openings are smaller 
than the diameter of the cylinders, the water enclosed at any time is 
a mixture derived from the few fathoms just passed through. This 
is no objection in deep-sea work, provided an adequate locking 
arrangement is employed. When a simple valved cylinder is used 
the results are untrustworthy, because any check on the line opens 
the valves and allows the water to get mixed. 
The oldest method of getting water from a definite depth was 
by sinking a corked bottle full of air. It was sent down 100 
fathoms or so, and when hauled up it was found still corked, but 
full of water. This is accounted for by two theories ; the water 
either filters through the cork, or, at a certain depth, the pressure 
suffices to drive the cork in, the bottle instantly fills, and as it is 
drawn up, the contained water being relieved from pressure, expands 
and fixes the cork firmly in its place. This method of collecting 
water has been employed by many chemists, by Forchhammerf 
and Yon Bibra} in particular; but it is very unsatisfactory. 
Sir Humphry Davy invented, for Sir John Ross’s Arctic voyage 
of 1818, a water-bottle § which was found to be uncertain in its 
working. 1 1 It was a strong pear-shaped copper vessel, with a stop- 
cock at the upper end, which was opened, and, after the bottle filled, 
closed again by levers actuated by a piston working in an air-tight 
side-tube, and capable of adjustment enabling it to act at any depth 
from 5 to 80 fathoms. The arrangement was entirely automatic, 
and as the pressure at the required depth opened and closed the 
bottle it was even unnecessary to measure the line as it was payed out. 
* Described and figured, Chall. Rep. Narrative, i. (1884), pt. 2, p. 3. 
+ Phil. Trans., civ. (1865), p. 203. 
J Liebig’s Annalen, lxxvii. (1851), p. 90. 
§ Described and figured, Jour. Scien. and the Arts, v. (1818), p. 231. 
|| Voyage of Discovery in H.M. ships “Isabella” and “Alexander,” 1819, 
Appendix. 
