APRIL 11, 1884. ] 
has been in the employ of the English, Wryville 
Thomson -said, that he one day saw the inventor 
scattering on the floor pieces of money, and raising 
them again with the greatest ease by means of the 
Fie. 8.— Old (1) and new (2) dredging-lines, natural size. 
instrument he had contrived. This shows the impor- 
tant use of the teeth with which the sides of the frame 
are furnished. 
To protect the net, which would be torn to shreds 
by the rocks as it is drawn along, it is enclosed either 
in another net of iron links, or in a sail-cloth or leather 
bag. Its lower end acts as a kind of clog, being so 
arranged that objects, once having entered, cannot 
escape. The front part of the dredge is sometimes 
furnished with a rake, to turn the mud or sand of the 
bottom, and thus to liberate the animals found there. 
During the explorations of the Travailleur, dredges 
were sometimes used which, by a special mechanism, 
descend, closed, to the bottom, and open only when 
they reach it. But, whatever the plan of the dredge, 
the results are not valuable; for these machines are 
almost immediately filled with sand or mud, which, 
on account of the sail-cloth or leather bag, cannot be 
released. Generally, when a dredge is raised, a sack- 
ful of sediment is all that is brought on board. They 
are, besides, very inconvenient. 
During one of the cruises of the Porcupine, Wyville 
Thomson noticed, that, while the interior of the 
dredge enclosed very few interesting specimens, a 
number of echinoderms, corals, and sponges, caught 
on the outside of the sack, and sometimes even on 
the upper part of the chain of the dredge, came to the 
surface. ‘‘This suggested,” said he, ‘‘many expedi- 
ents; and finally Capt. Calver sent down half a dozen 
of the ‘swabs’ used for washing the decks, attached 
to the dredge. The result was marvellous. The 
tangled hemp brought up every thing rough and 
movable which came in its way, and swept the bot- 
tom as it might have swept the deck. Capt. Calver’s 
invention initated a new era in deep-sea dredging.”’ 
It is certain that the use of tangles gives good re- 
sults; but they, too, are very inconvenient, as Wyville 
Thomson was forced to acknowledge. 
“The tangles,’’ he says, some pages beyond the 
passage quoted above, ‘‘ certainly make a sad mess of 
the specimens; and the first feeling is one of woe, as 
SCIENCE. 
451 
we undertake the almost hopeless task of clipping out 
with a pair of short nail-scissors the mangled remains 
of sea-pens, the legs of rare crabs, and the dismem- 
bered disks and separated arms of delicate crinoids 
and ophiurids. We must console ourselves with the 
comparatively few things which come up entire, stick- 
ing to the outer fibres, and with the reflection, that, 
had we not used this somewhat ruthless means of 
capture, the mutilated specimens would have re- 
mained unknown to us at the bottom of the sea,’’ 
The description is exact; but one must examine the 
condition of the larger part of the specimens brought 
up by the tangles, to understand the despair of the 
naturalists in their search among inextricable confu- 
sion of threads, and remains of rare, often unknown, 
animals. We thus see the necessity of some better 
method of collecting and bringing up the animals. 
During the campaign with the Blake, in the Gulf 
of Mexico, Mr. Agassiz used trawls, a kind of large 
net common on our coasts among fishermen, and ob- 
tained good results. On board the Talisman, trawls 
of the same kind, with an opening two or three 
metres in extent, were employed. ‘The dredges are 
very rarely used, these being reserved for the explora- 
tion of rocky bottoms, where the sharp edges would 
cut the net into pieces. In fig. 10 is shown one of 
the trawls used on the Talisman. By an examina- 
tion of this cut, one can understand the arrange- 
ment of the net, which is such, that, on whatever 
side the machine reaches the bottom, it is always 
drawn to some purpose. There are two pockets, one 
inside the other. At the end of the outer one a large 
cast-iron ball is tied, while the inner pocket opens at 
its lower end, preventing objects which have entered 
from getting free again. During the course of the 
cruise, Commandant Parfait had one of the tangles 
ai 
Fie. 9.— Action of the ‘ accumulator.’ 
placed at the very bottom of the trawl, with remarka- 
ble results. The success was due to the fact that a 
crowd of all the little animals, crustaceans, mollusks, 
and ophiurans, which, drawn in with the water into 
