As an electrised point with either kind of electricity causes a stream of air to pass from it in the direction of the point, it seems to affect the air much in the same manner as the fluid matter of heat affects it; that is, it will not readily pass through it, but will adhere to the particles of air, and is thus carried away with them. From this it will also appear, that points do not attract electricity, properly speaking, but suffer it to depart from them; as it is there less attracted to the body which it surrounds, than by any other part of the surface. And as a point presented to an electrised conductor facilitates the discharge of it, and blows the flame of a candle towards the conductor, whether vitreous or resinous electricity be accumulated upon it; it follows, that in both cases some electric matter passes from the point to the conductor, and that hence there are two electric ethers; and that they combine or explode when they meet together, and give out light and heat, and occupy less space in this their combined state, like the union of nitrous gas with oxygen gas. IV. _Accumulation of Electric Ethers by Contact._ The electric ethers may be separately accumulated by contact of conductors with nonconductors, by vicinity of the two ethers, by heat, and by decomposition. Glass is believed to consist in part of consolidated resinous ether, and thence to attract an electric atmosphere round it, which consists of a greater proportion of vitreous ether compared to the quantity of the resinous, as mentioned in Proposition No. 4. This atmosphere may stand off a line from the surface of the glass, though its attractive or repulsive power may extend to a much greater distance; and a more equally mixed electric atmosphere may stand off about the same distance from the surface of a cushion. Now when a cushion is forcibly pressed upon the surface of a glass cylinder or plane, the atmosphere of the cushion is forced within that of the glass, and consequently the vitreous part of it is brought within the sphere of the attraction of the resinous ether combined with the glass, and therefore becomes attracted by it in addition to the vitreous part of the spontaneous atmosphere of the glass; and the resinous part of the atmosphere of the cushion is at the same time repelled by its vicinity to the combined resinous ether of the glass. From both which circumstances a vitreous ether alone surrounds the part of the glass on which the cushion is forcibly pressed; which does not, nevertheless, resemble an electrised coated jar; as this accumulation of vitreous ether on one side of the glass is not so violently condensed, or so forcibly attracted to the glass by the loose resinous ether on the other side of it, as occurs in the charged coated jar.