200 THREE CRUISES OF THE “ BLAKE." 
I made no attempts to use the tow-net to ascertain the pre- 
sence of foraminifera, radiolaria, or other pelagic animals, at a 
distance from the surface. All naturalists familiar with the use 
of the dip-net, the tow-net, or with their modifications first em- 
ployed below the surface by Baur, know that the pelagie ani- 
mals are driven from the immediate surface by winds and rain, 
or by some other cause, into moderate depths, where they may 
always be procured, while at greater depths they fail to be found. 
Such, at least, has been the experience of Johannes Müller, 
Claparéde, and others, who have followed their method of fish- 
ing either at the surface or a httle below 1t. 
The evidence of specimens brought up by the * Challenger" 
nets from intermediate depths is inconclusive, since the ordi- 
nary tow-nets were used. These were lowered open, kept open 
while towing, and remained open while coming up. It is per- 
fectly true, visti by differentiation of the contents of the several 
nets at one locality, some approximate results might be obtained, 
if the work were carried on for a long period ; Бш an bbcasionai 
haul taken by itself means nothing. The important desideratum 
is to devise a tow-net which will go down closed to any depth re- 
quired, will then open and tow while the ship is in motion, and 
close again within a reasonable distance as it comes up. The 
collecting cylinder devised by Lieutenant-Commander Sigsbee 
meets some of these requirements! He accompanied us on the 
* Blake,” to superintend in person its first trial. It was sent 
down in thirty fathoms of water, from five to twenty-five fath- 
oms, with quite a fresh breeze blowing, at about eleven in the 
morning, in full sunlight,—a time when, with a smooth sea, 
the pelagie animals would all have been on the surface. The 
cylinder worked most satisfactorily, and brought up а few Calani, 
hydroid medus:e, such as usually occur at the surface. A few 
slight changes were suggested by the граб and Commander 
Bartlett vbouismibndae the addition of a wire-gauze trap, to 
facilitate the washing out of microscopic animals. 
On the Ist of July the Sigsbee cylinder was tried for the 
second time, in Lat. 89° 59' 16" N., Lon. 70° 18’ 30" W., i 
two hundred and sixty fathoms of water. The surface was 
1 Described in the chapter on the Equipment of the “ Blake." 
