Though the contact of a cushion on the whirling glass is the easiest method yet in use for the accumulation of the vitreous electric ether on an insulated conductor; yet there are other methods of effecting this, as by the vicinity of the two electric ethers with a nonconductor between them. Thus I believe a great quantity of both vitreous and resinous electric ether may be accumulated in the following manner. Let a glass jar be coated within in the usual manner; but let it have a loose external coating, which can easily be withdrawn by an insulating handle. Then charge the jar, as highly as it may be, by throwing into it vitreous electric ether; and in this state hermetically seal it, if practicable, otherwise close it with a glass stopple and wax. When the external coating is drawn off by an insulating handle, having previously had a communication with the earth, it will possess an accumulation of resinous electric ether; and then touching it with your finger, a spark will be seen, and there will cease to be any accumulated ether. Thus by alternately replacing this loose coating, and withdrawing it from the sealed charged jar, by means of an insulating handle; and by applying it to one insulated conductor, when it is in the vicinity of the jar; and to another insulated conductor, when it is withdrawn; vitreous electric ether may be accumulated on one of them, and resinous on the other; and thus I suspect an immense quantity of both ethers may be produced without friction or much labour, if a large electric battery was so contrived; and that it might be applied to many mechanical purposes, where other explosions are now used, as in the place of steam engines, or to rend rocks, or timber, or destroy invading armies! The principle of this mode of accumulating the two electric ethers in some measure resembles that of Volta's Electrophorus and Bennet's Doubler. VI. _Accumulation of electric ethers by heat and by decomposition._ When glass or amber is heated by the fire in a dry season, I suspect that it becomes in some degree electric; as either of the electric ethers which is combined with them may have its combination with those materials loosened by the application of heat; and that on this account they may more forcibly attract the opposite one from the air in their vicinity. It has long been known, that a siliceous stone called the tourmalin, when its surfaces are polished, if it be laid down before the fire, will become electrified with vitreous, or what is called positive electricity on its upper surface; and resinous, or what is called negative electricity on its under surface; which I suppose lay in contact with somewhat which supported it near the fire.