18 PERCY SLADEN TRUST EXPEDITION. 
obvious that with the slacker ground-ropes a much greater grip of the bottom is obtained. 
‘The sizes employed by us were 9, 6, and 4:5 feet, the bags three or four times these lengths 
and made of twine, 1—2-inch mesh. To give weight we had to lash old firebars on to 
the stirrups, but it would have been far better to have made all the parts much stronger 
and heavier. A lead must always be attached to the bag, or in letting out quickly it 
will often be caught up over the mouth of the trawl. These trawls tend to twist up to 
a lesser degree than the dredges, and the arrangement of swivels, mentioned before, on 
the end of the warp is less necessary. Their bridles are of considerable length, and 
hence it is difficult in any vessel to swing their bags clear of the water, unless they can 
pass through the block together with the swivels. We experienced considerable 
inconvenience at first, since we hung our indicator-block on the end of the davit. It ought 
to have beena snatch-block that would open on one side; we could have then removed the 
warp from it and taken the strain on a second larger block, which up to that time would 
have been hanging from the same davit. 
Another instrument with which we had provided ourselves—and the use of which 
we strongly recommend—was the Ekhman Current Meter. It consists of a frame 
through the centre of which a wire cord can be passed, having a heavy weight at its end. 
A serew and indicator on one side are balanced by a large vane on the other to keep the 
screw in position facing the current. Messengers start and stop the meter. There is a 
compass in a box open to the water below the meter, and as the screw revolves, shot are 
dropped on to the top of the compass itself. This has the north point deeply grooved, 
so that the shot are bound to run down it. They then fall into the box, which is 
divided up into compartments. By examining the position of the shot in the box in 
relation to that of the screw the direction of the current is clearly shown. For use the 
ship should be anchored, but it would be possible to rest the lower weight on the bottom 
and buoy the wire. The meter requires to be nicely adjusted and continually tested, but 
for direction the arrangement is a great advance on the compass clamped by a messenger, 
which one of us (Gardiner) used in the Maldives and Laccadives in 1899-1900 (fig. 4). 
lor the plankton or pelagic-fauna work we used the same wire and arrangements as 
we employed for reversing thermometers and water-bottles. In the collecting-gear 
employed we (having little experience of our own) in the main followed the directions of 
Dr. G. H. Fowler, who most kindly gave us every assistance in his power. For ordinary 
purposes we employed two kinds of nets—iron rings of 13 and 7 inches in diameter, nets 
of silk bolting-cloth, 6 and 3 feet in length and of 60 and 180 meshes to the inch. Most 
of the rings were fitted with a pair of clamps with butterfly-nuts, which came unscrewed 
in a few turns, so that they might be readily affixed to a vertical wire. For the smaller 
nets we used 4-0z. bottles, while for the larger we introduced a modification in the shape 
of vessels made of aluminium. These tended to float upside down, unless filled with 
water before being lowered into the sea, but they undoubtedly by their lightness allow 
the hag of the net to float out more horizontally, so that the organisms caught are less 
damaged and probably more numerous. We also used a large net, 4 feet in diameter 
at the mouth, with long bridles and a 2-gallon tin at its end. Its net was made of the 
best mosquito-cloth 8 meshes to an inch and 16 yards in length, so as to allow the water 
