430 MANUAL OF THE MOLLUSCA. 



weather, with a light breeze. The Yacht is brought to the wind (by puttiug 

 up the helm), the foresheet hauled to windward, mainsail hauled up, and 

 luizen 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. 

 AYhen the dredge is to be hauled in, the rope is passed through a moveable 

 block, fixed to the shrouds, and the whole strength of the crew (15 hands) 

 called into requisition if necessary. When the depth does not exceed 50 

 fathoms, the boat, with three men and the two dredgers, is used. 



If the dredge gets fouled, the ri;pe is passed into the boat, brought over 

 tKe dredge, and hauled up. In very deep water (150 fm.) 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 Avith two sieves, one 

 " \ inch," the other very fine. They are made of copper wire, and one fits 

 into the other. The d:edge is emptied into the coarse sieve and washed in 

 the sea from the boat , or if in the yacht, they are ])laced in an iron frame, 

 over the side of the vessel, and buckets of w'ater poured on. The sediment 

 retained in the fine sieve may be dried and examined at leisure, lor minute- 

 shells. 



The following " dredging-papers," kept on the plan recommended by 

 Prof. E. Forbes, have been selected by Mr. Barrett, to illustrate the kind of 

 shells found at various zones of depth. 



Note. — The shell-fish obtained by dredging should be at once boiled, and 

 the animals removed, unless wanted for examination (p. 441). The bivalves 

 gape, and require to be tied with cotton ; the opercida of the univalves should 

 be secured in their apertures with w^ool. 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 chlo- 

 ride of lime may be necessary to deodorize them. 



M. Petit de la Saussaye has given very full instructions for collecting 

 and preserving shells, in the Journal 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 prepara- 

 tion is expensive and dangerous. 



Dredges and other apparatus, glazed boxes, and glass tubes for specimens, 

 may be obtained of G. Sowerby, 70, Great Russell Street, Bloomsburj' , 

 and of R. Damon, Weymouth. 



