MUSEUM OF COMPARATIVE ZOOLOGY. 63 
EXPLANATION OF PLATE L 
From sketches by Captain Sigsbee. 
The annexed sketches of Captain Sigsbee's water-bottle, Pl. I, Figs. 1, 2, will 
interest those who have used the apparatus for obtaining water from great 
depth. The method of closing the valves is entirely different from that em- 
ployed by other hydrographers. It seems far more accurate for deep water 
than the water-bottles used by the “Challenger,” and by the Swedish or the 
German expeditions. The tests to which it has been submitted show that it 
closes in a depth of about ten to fifteen fathoms, that it then remains hermeti- 
cally sealed, and that no amount of pitching or stopping can open the valves 
again, when once closed. For serial lines the water-bottles and thermometers 
were not sent down on the sounding line, but a stronger steel cord, three 
eighths of an inch in circumference, was used, to which the thermometers 
and bottles were attached. No attempt was made on our trip to make any 
chemical examination of the water from different depths. The small size of 
the vessel made a chemical laboratory out of the question, and it seems more 
natural for another expedition to establish a laboratory on shore at some point 
near deep water, and carry the bottles to the laboratory for analysis, 
Fig. 1 gives a view of Captain Sigsbee's water-bottle, seen facing the frame 
of the propeller (p), by which the valves are closed. As long as the bottle 
sinks, the valves remain open. These are connected by a rigid rod, extend- 
ing through the centre of the bottle. The moment it is hauled up the pro- 
peller is forced down on the shaft, until it presses with all its force upon the 
upper valves, and when this takes place it also slips out from its connection 
with the upper end of the shaft, so that, should the bottle be lowered again, 
the propeller eould not rise and the valves be opened. 
Fig. 2 shows the same bottle, at right angles to Fig. 1, with the mode of 
attaching it to the steel rope (z) by means of a spring (a). This is done in an 
instant, and the bottles firmly held in place by the double spring holding the 
rope at two points. A similar mode of attachment for the deep-sea thermom- 
eters would be a great saving of time when making a serial line of temper- 
atures, 
Fig. 3 shows the mouth of an ordinary dredge, with the rope stopped round 
it to prevent its digging into the mud, as first applied by Captain Sigsbeo, 
Fig. 4 gives a sketch of the iron frame of the flat dredge, with the mode of 
attaching the tangles, figured with its covering and appendages in Fig. 5. 
