446 REPORT—1899, 
addition of extra weight to any degree that might appear to be required. 
The wire employed was provided by Messrs. Latch & Batchelor, Limited, 
of Birmingham. They describe it as No. 16 G, and give its breaking 
strain as 790 pounds. 
The essential parts of the frame are the same as in Giesbrecht’s net, 
but the modifications introduced are in the direction of a much greater 
simplicity. A quadrangular jointed metal frame slides up and down a 
cylindrical axis, formed by a stout rigid metal tube, which is furnished 
with a guide. When the frame is opened, the aperture is diamond- 
shaped ; when shut, the two upper limbs of the frame approximate 
tightly to the corresponding lower limbs. Both pairs of limbs can be 
supported in the closed position at the tov of the tubular axis by metal 
springs, on the principle employed by Dr. H. R. Mill in his well-known 
self-locking water-bottle. Owing to the fact, however, that the releasing 
gear had to be doubled in the case of the net, the set of springs which 
support the lower limbs of the frame were attached inside the tubular 
axis, which is perforated at three points for the protrusion of the sup- 
porting edges of the springs. Release of the frame is effected in each case 
by the action of a metal cap which can be driven over the springs by the 
action of a messenger. The first messenger (a narrow one) drives down 
the inner cap and releases the lower limbs of the frame, which then 
descend by their own weight and open the net to its utmost extent ; the 
second messenger (a broad one) is arrested by the outer cap, drives it 
down, and releases the upper part of the frame, thus closing the net again, 
but in this case at the bottom of the axis, instead of at the top. By means 
of messengers both movements are thus under the control of the operator 
on the deck of the ship, whatever be the depth to which the net is lowered. 
Another important departure from the Giesbrecht net, whether in its 
original form, or as modified by the Prince of Monaco, consists in the 
method by which the proper orientation of the net is ensured. The wire, 
in fact, is attached to a central pivot upon which the tubular axis of the 
frame, which bears all the weight, is free to rotate. Friction is reduced 
to a minimum by means of ball bearings. In this way the possibility of any 
revolution of the net round a vertical axis, either during descent, towing, or 
ascent, as a consequence of the twisting of the wire, is completely avoided— 
a very important matter, for if the frame were to revolve during its descent, 
the gauze net attached to it would be wrapped round the axis or the hori- 
zontal limbs of the frame, and the opening of the net would be impeded, 
and probably quite prevented. On no occasion, however, has such an 
accident happened—a fact which bears witness to the efficiency of the 
means taken to prevent it. The net never failed to come up to the sur- 
face properly closed, so that the reliability of the results obtained by the 
net can be confidently assumed. Although on this occasion it is not 
proposed to go into any details, Mr. Garstang reports that the difference 
between the plankton of different levels as revealed by this new net were 
in many cases of a most conspicuous character, a fact which will be fully 
demonstrated in the final report of the Committee. The various hauls 
made by the net at different times of the day and night also show in a 
clear and convincing manner the effect of light and darkness upon the 
vertical movements of pelagic organisms in the Channel waters, 
It is consequently proposed to continue the investigations until 
February 1900, in order to complete a full year’s survey under identical 
conditions with the same apparatus, 
