186 Uses of

putrid itself, but also greatly contributes to theputrefying of any adjoining Wood, &c. Andthis seems to be the probable Reason why,when fresh Air is admitted into an Ice-house,by opening the Doors to take out some Ice,then the Ice melts fast; but when the Doorsare closed again, so as to prevent the Entranceof fresh Air, stored with a new Supply ofAcid,| then the Degree of melting abates, inproportion as the last admitted Air is by theIce in the Ice-house deprived of its acidSpirit. Thus common Salt mixed withpounded Ice, does, by virtue of its Acid, dis-solve the Ice fast, and that even though theCold is thereby, at the same time, increasingto a very intense Degree for about seven Mi-nutes j after which the intense Cold graduallyabates. Mr. Reid therefore proposes the put-ting Salt among the Timbers of Ships, as aPreservative; and if the Salt be mixed amongOakham, not only the less Salt will suffice,but it will thereby be the better retained inall Parts among the Timbers. And as heobserves in his Treatise on the Acid of Tar,that the Finlanders , by painting the Timberof their Houses with this Acid, worked upwith red Okre pulverized, make them lastfor ioo or 150 Years or more; and that

dry