I. “All terrestrial substances, as well as the atmosphere which surrounds the earth, are full of electric matter.” The proofs of this are very easy. There is no place of the earth or sea where the electric fire may not be collected, by making a communication between it and the rubber of an electric machine. Therefore, considering that the whole earth is moist, and that moisture is a conductor of electricity, and that every part of the earth must thus communicate with another, it is certain that the electric matter must diffuse itself as far as the moisture of the earth reaches; and this may reasonably be supposed to be to the very centre. The case is equally clear with regard to the atmosphere. The extract from Mr. Cavallo’s journal, given in the chapter upon atmospheric electricity, is a sufficient proof that the atmosphere is full of electric matter. II. “Glass, and other electric substances, though they contain a great deal of electric matter, are nevertheless impermeable by it.” The principal arguments for the impermeability of glass by the electric fluid are drawn from the phenomena of the Leyden phial. It is very plain that there is, in charging this phial, an expulsion of fire from the outside, at the same time that it is thrown upon the inside. This appears from numberless experiments, but is most readily observable in the following. Let a coated phial be set upon an insulating stand, and the knob of another phial brought near its coating. As soon as sparks are discharged from the prime-conductor to the knob of the first, an equal number will be observed to proceed from its coating to the knob of the second. This is very remarkable, and an unphilosophical observer will scarce ever fail to conclude, that the fire runs directly through the substance of the glass. Dr. Franklin however concludes that it does not, because there is a very great accumulation of electricity on the inside of the glass, which discovers itself by a violent flash and explosion, when a communication is made between the outside and inside coatings. But it must be confessed, there is here no other reason for concluding the glass to be impermeable, than the _probability_ that the electric matter is accumulated on one side of the glass and deficient on the other. Another argument against the permeability of glass and other electrics is, that coated phials can receive but a very slight charge when their outside coating is insulated, and this can be effected only with a very powerful machine. III. “The electric fluid violently repels itself, and attracts all other matter.” The proofs of this position have been so abundantly given in the course of this work, particularly in the chapter on electric attraction and repulsion, that we think it entirely superfluous to repeat them here.