ON COLLECTING SHELLS. 143 
in calm weather, with a light breeze. The yacht is brought to 
the wind (by putting up the helm), the foresheet hrzied to 
windward, mainsail hauled up, and mizen taken in; the gaff 
topsail also hauled up; she then drifts to leeward, and the 
dredge is thrown overboard to windward, with the line made 
fast amidships; the spare line being coiled up so as to be given 
out readily. When the dredge is to be hauled in, the rope is 
passed through a moyable block, fixed to the shrouds, and the 
whole strength of the crew (fifteen hands) called into requisition, 
if necessary. When the depth does not exceed 50 fathoms, the 
beat, with three men and the two dredgers, is used. 
If the dredge gets fouled, the rope is passed into the boat, 
brought over the dredge, and hauled up. In very deep water 
(150 fathoms) the line is carried forward and made fast to the 
bows, and the yacht itself hauled up till right over the dredge, 
which is then recovered without difficulty. 
The contents of the dredge are washed, and sifted with two 
sieves, one ‘‘+-inch,”’ the other very fine. They are made of 
copper wire, and one fits into the other. The dredge is emptied 
into the coarse sieve and washed in the sea from the boat, or if 
in the yacht, they are placed in an iron frame, over the side 
of the vessel, and buckets of water poured on. The sediment 
retained in the fine sieve may be dried and examined at leisure, 
for minute shells. 
The following ‘‘dredging-papers,” kept on the plan recom- 
mended by Professor EH. Forbes, have been selected by Mr. 
Barrett, to illustrate the kind of shells found at various zones 
of depth. 
The shell-fish obtained by dredging should be at once boiled, 
and the animals removed, unless wanted for examination (p. 153). 
The bivalves gape, and require to be tied with cotton; the 
opercula of the univyalyes should be secured in their apertures 
with wool. The small univalves may be put up in spirit, or 
glycerine, to save time. In warm climates the flies and ants 
assist in remoying any remains of the animals left in spiral 
shells, and chloride of lime may be necessary to deodorise them. 
M. Petit de la Saussaye has given yery full instructions for 
collecting and preserving shells, in the Jowrnal de Conchyliologie 
for 1850, p. 215, and 1851, pp. 102, 226. 
It is stated that both the form and colour of molluscous 
animals may be preserved in a saturated solution of hydro- 
chlorate of ammonia (10 parts) and corrosive sublimate (1 part 
—first dissolved in alcohol), but the preparation is expensive 
and dangerous. 
