Page:Voyage in search of La Perouse, volume 1 (Stockdale).djvu/103

Dec.] hot climate. A great quantity of inflammable air is then diengaged from it; o that a peron who goes into the hold where it is towed, runs the hazard of being uffocated. This, however, is an accident that very rarely happens, as a part of the noxious vapours are dicharged by the paage leading into the hold. Nevertheles, thee vapours frequently give rie to nervous fevers amongt the crew, the malignity of which, is in proportion to the heat by which the decompoition of the water is effected.

As this gas, the pecific gravity of which was firt determined by Prietley, is coniderably lighter than atmopherical air, and has likewie very little attraction for the water; it is very eaily eparated, o as to retore water to its former purity; nothing more being neceary than to agitate the fluid for the pace of a quarter of an hour.

We had a machine on board which was perfectly adapted to this purpoe. It conited of a large bucket, about five cubic feet in capacity, which being filled to about two-thirds with water, four large flat pieces of iron were turned round in the middle of the veel, by means of a handle and balance-wheel. By this operation the water in the bucket was violently agitated, and whilt the inflammable air, with which it had been impregnated, was diengaged, it aborbed a quantity