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 hauled to 

 windward, mainsail hauled up, and mizen taken in; the galf 

 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 movable block, fixed to the shrouds, and the 

 whole strength of the crew (fifteen hands) called into requiaition, 

 if necessary. T\Tien the depth does not exceed 50 fathoms, the 

 boat, 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 " 5 -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 E. 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 univalves should be secured in their apertui'es 

 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 removing 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 very full instructions for 

 collecting and preserving shells, in the Journal de Conchy liologie 

 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. 



