36 THREE CRUISES OF THE “ BLAKE." 
several operations of lowering, dragging, and hauling back re- 
mained open; this cannot be regarded as affording acceptable 
evidence of the habitat of such specimens as were obtained. It 
yecame an interesting problem on the “ Blake” to determine 
|; teresting probl the “ Blal 
accurately how far these pelagic forms really extend. Lieu- 
enant-Commander Sigsbee contrived a machine intended to 
t t-C ler Sig 
furnish means for solving this problem. It consisted of a cop- 
per cylinder to: be sent down closed on a collecting expedition 
to any depth desired, when it was opened by a messenger ; being 
1 Sigsbee’s apparatus consists of a cylinder, covered with 
gauze at the upper end, and having a flap-valve at the lower 
end. ‘The cylinder is heavy enough to acquire a rapid vertical 
descent between auy two depths, — the valve during the descent 
keeps open, but remains closed during the processes of lowering 
and hauling back with the rope. An idea of what it is intended 
to effect may thus be stated briefly : specimens are to be ob- 
tained between the intermediate depths « and 5, the former 
being the uppermost. With the apparatus in position, there is 
at а ће cylinder suspended from a friction-clamp in such à way 
that the weight of the eylinder and its frame keeps the valve 
closed ; at b there is a friction-buffer. Everything being ready, 
a small weight or messenger is sent down, which on striking the 
clamp disengages the latter and also the cylinder, when mes- 
senger, clamp, and cylinder descend by their 
own weight to b, with the valve open dur- О Ор 
ing the passage. When Ше cylinder-frame А 
. a LH A " Ü 
strikes the buffer at b, ће valve is thereupon fir sem 
closed, and it is kept closed thereafter by the 
\ 
lo 
weight of the messenger, clamp, and cylinder. \ 
The friction-buffer, which is four inches long, \ 
; , \ 
may be regulated on board to give as many feet \ 
of cushioning as desired. The accompanying 
sketch of the trap (Fig. 33) explains itself. ‘The 
copper cylinder A is retained in place by screw- 
bolts. It is riveted to a wrought-iron frame 
D, has a flap-valve C, fastened to a long lever 
D, pivoting at Æ. The top of the cylinder is 
covered by a wire sieve, and in addition there 
is a wire-gauze funnel or trap M, inside the 
cylinder. The eylinder is hung to the friction- 
clamp K, by an excentrice tumbler P, which is 
released whenever the messenger X strikes it, 
allowing the messenger, cylinder, and clamp to 
travel with the valve open till it strikes at the 
requisite depth the buffer Q. The valve is then 1 
closed, the eylinder drawn up, and the contents Fig. 33, — Sigsbee's Gravitating 
of the sieves carefully examined on deck. Trap. (Sigsbee. ) 
