
ON A DEEP SEA TOW-NET, ETC. 101 
disadvantage is that the stretch of water examined can 
only be extended vertically not horizontally. 
Another invention is that of Mr. Alexander Turbyne,* 
captain of the steam yacht ‘“‘ Medusa,” belonging to the 
Scottish Marine Station. A net of the ordinary type can 
be constricted by a rope passing round it a little behind 
the metal hoop. It is let down thus, and then the con- 
stricting cord is slackened, to be tightened again before 
being drawn up. The disadvantage of this apparatus is 
that it requires two ropes, which are liable to become 
entangled with each other. 
Still another apparatus was contrived by Professor 
Pavesi, + for his researches into the abyssal fauna of the 
Ttalian lakes, which worked by means of a sliding weight, 
but it could only be opened when it reached the required 
depth and not closed again. An improvement, in which 
this drawback has been overcome, is described by MM. 
Pouchet and Chabry,{ but I confess that I was unable 
from their very brief description to understand its action, 
even when aided by the wood-cuts, which accompany an 
article in the same journal by the Prince of Monaco. § 
Captain Palumbo, of the Italian corvette ‘‘ Vettor 
Pisani,’ devised an automatic net which was let down 
with the thermometer, and is said to have worked 
satisfactorily. || 
All these (except perhaps the last, regarding which I 
have no detailed information) depend upon the action of a 
“messenger,” or perforated weight which runs down the 
cord to which the net is attached—the principle adopted 
* The Scottish Marine Station for Scientific Research; its Work and 
Prospects. Edinburgh, 1885, 8vo. 
+ Atti Soc. Ven.-Trent. Padova, vol. viii., pp. 341—343, pl. viii., 1883. 
+ Comptes rendus soc. biol., sér. 8, t. iv., pp. 602—604, 1887. 
§ Tom. cit., pp. 661—664, cuts. 
|| Nature, vol. xxx., p. 365, 1884. 
