hot climate. A great quantity of inflammable air is then diſengaged from it; ſo that a perſon who goes into the hold where it is ſtowed, runs the hazard of being ſuffocated. This, however, is an accident that very rarely happens, as a part of the noxious vapours are diſcharged by the paſſage leading into the hold. Nevertheleſs, theſe vapours frequently give riſe to nervous fevers amongſt the crew, the malignity of which, is in proportion to the heat by which the decompoſition of the water is effected.
As this gas, the ſpecific gravity of which was firſt determined by Prieſtley, is conſiderably lighter than atmoſpherical air, and has likewiſe very little attraction for the water; it is very eaſily ſeparated, ſo as to reſtore water to its former purity; nothing more being neceſſary than to agitate the fluid for the ſpace of a quarter of an hour.
We had a machine on board which was perfectly adapted to this purpoſe. It conſiſted 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 veſſel, by means of a handle and balance-wheel. By this operation the water in the bucket was violently agitated, and whilſt the inflammable air, with which it had been impregnated, was diſengaged, it abſorbed a
quantity
