ON IMPROVING AND EXPERIMENTING WITH A DEEP-SEA TOW-NET. 471 
Report of the Committee, consisting of Professor Happon, Mr. W. E. 
Hoy e (Secretary), and Professor W. A. HERDMAN, appointed 
for improving and experimenting with a Deep-sea Tow-net, 
for opening and closing under water. 
Tux report which this Committee had the honour of presenting at the 
last meeting of the Association concluded with the statement that an 
attempt was being made so to modify the net that it should be opened 
and closed, not by the agency of sliding weights, but by an electric 
current. The work of the past twelve months has been a successful 
endeavour to carry out this programme. 
The new apparatus, of which hitherto only a provisional model has 
been made, is in its main principles very similar to the one already 
described. No change of importance has been made in the net itself, but 
she Committee has procured a net-frame, made according to the design 
advocated by Professor Hensen, of Kiel, which contains some improve- 
ments in points of detail, and appears likely to render very efficient service. 
The mode of opening and closing the net by the successive detachment 
of two cords, or links, has been retained; but these are now looped 
round the shorter arms of two bell-crank levers, the longer extremities of 
which rest upon two studs projecting laterally from the sector of an 
escapement wheel near its circumference. The lengths of the levers are 
so adjusted that when the first tooth of the escapement is liberated one 
of them falls, whilst the second is retained until the third tooth has been 
liberated. 
The escapement sector is actuated by aspring, and its movements are 
controlled by an electro-magnet, whose armature is attached to, or rather 
made solid with, the escapement itself. 
The current passes to the magnet down a wire in the rope by which 
the net is towed, and when the net is let down closed the circuit is open. 
As soon as the desired depth has been reached contact is made, the 
movement of the armature releases the first tooth of the escapement, and 
the net opens. When the circuit is broken the second tooth of the sector 
is caught by the escapement, and held until a second contact sets free the 
other lever and closes the net. 
The apparatus has been tried, first, in a fresh-water pond in the 
vicinity of Manchester, and secondly, on one of the dredging excursions 
of the Liverpool Marine Biology Committee in the s.s. Hyena. The 
facilities for experiment on this occasion were extremely great, as the 
vessel was provided with a dynamo, and the apparatus worked success- 
fally to a depth of from ten to fifteen fathoms. 
The funds at the disposal of the Committee were not sufficient to 
enable them to hire a vessel for making further trials in deep water, and 
their efforts to obtain an opportunity of doing so by any other means 
have failed ; but it is hoped that the means may be forthcoming during 
the next twelve months. 
The thanks of the Committee are due to Messrs. B. and S. Massey, 
who have constructed the new lock gratuitously, and thus enabled the 
work of the Committee to be done much more economically than would 
otherwise have been possible; to the Liverpool Marine Biology Com- 
mittee for the possibility of utilising the cruise of the Hyena for the 
trials; to Mr. J. A. Henderson for the loan of one of his very conveniently 
