WHALE- F1SHERV. 221 



not necessary to lay open more of the ground tier at 

 a time, than three or four casks extended in length. 

 The water which is discharged from the casks 

 in the hold, provided they have been before in use, 

 gives out a great quantity of a strong disagreeable 

 vapour, consisting probably of sulphuretted and 

 phosphuretted hydrogen, with a mixture of other 

 gaseous fluids, produced by the decomposition of 

 the oleaginous, and other animal substances, left in 

 the casks after former voyages. This decomposi- 

 tion seems to be encouraged, if not wholly produced, 

 by the action of the water on the animal matter; 

 because the same casks, if bunged close, when 

 empty, give out but a small quantity of gas and 

 that of inferior pungency. The gas proceeding 

 from oily casks, having contained water, resembles, 

 in some degree, though vastly more pungent, the gas 

 evolved by " bilge water/' or the stagnant water 

 which rests among the timbers of a very tight ship. 

 The gas discharged from oily casks, is usually 

 stronger and more abundant, in proportion as the 

 water from which it is disengaged, has been a longer 

 time in the casks. A considerable quantity of it is 

 generated in the space of three or four months. 

 This gas blackens metals, even gold, restores some 

 metallic oxides, is disagreeable in respiration, and 

 affects the eyes of the persons employed in the hold, 

 where it is most abundant, so as to occasion ophthal- 

 mic inflammation, and frequently temporary blind- 

 ness. 



