46 BULLETIN OF THE 
together and closes the jaws of the net at the termination of the time of 
towing, and it remains closed until it reaches the surface. 
The 25th of February we made our first attempt with the modifica- 
tion of the Chun-Petersen closing net for towing at intermediate depths. 
On towing the same horizontally near the surface, so that we might 
watch the operation of the propeller in releasing the chains to open 
and then to close the net, it became very soon evident that but little 
reliance could be placed on the working of the propeller from the great 
pressure brought upon the shaft even during the slowest towing ; and 
from this the uncertainty of the action was so great that we could 
not feel satisfied that the net had closed and opened at the limits 
within which it was supposed to act. A very small net might work 
satisfactorily on this principle, and prove useful for attachment to a 
line for simultaneous serial observations after the fashion in use for 
serial thermometric work. This was a great disappointment, as from 
the first account given by Chun I inferred that there were no draw- 
backs to this machine. He mentions them in the account of his voyage 
to the Canary Islands. After this failure, we made no other attempt to 
use the machine, and subsequently our fishing at intermediate depths 
was carried on with the Tanner self-closing net, a description of which 
is given further on. 
Thanks to the ingenuity of Captain Tanner, we overcame these obsta- 
cles. He devised a net which could be closed at any depth by a mes- 
senger, and which worked to perfection at 200, 300, 400, and 1,000 
fathoms, and had the great advantage of bringing up anything it might 
find on its way up above the level at which it was towed. 
Figure 1 of Plate II. shows the general arrangement of the Tanner 
deep-sea closing net attached below the heavy shot, a, at the extremity 
of the wire dredging rope, 7. The net itself is suspended between two 
ropes, 7/, 7’, to which a sixty-pound shot, }, is suspended ; the extremity 
of the net is kept in place by a slack line, 7’. Around the lower part 
of the net a set of rings is fastened, through which passes a loop line, 
going out through pulleys, p. At each end of the loop line is fastened 
a fourteen-pound lead weight, w, which is hung close to the pulley by 
strings, /’/!, suspended by loops from a crank, ¢; this crank is securely 
fastened to the wire rope by a clamp, n, the details of which are seen in 
Figures 4 and 5. 
The outer net is made of twine netting, with a mesh for the support 
of the thinner and weaker muslin which lines the lower half of the net ; 
this in its turn is lined for its lower half with fine close-mesh silk bolting 
