of cards or a book, having a piece of tinfoil between several of its leaves, the electrical flash makes an impression in some of those metallic leaves, by which it seems as if the direction of the electric explosion had gone from the outside towards the inside, when on the other metallic leaves, the impression is in such a direction that it indicates the current of electrical fire to have made its way from the inside of the phial towards the outside, so that it appears to some electricians that, in the time of the explosion of an electrical phial, two streams of electrical fire rush at the same time from both surfaces, and meet or cross one another.

ANSWER

These impressions are not effects of a moving body, striking with force in the direction of its motion; they are made by the burs rising in the neighboring perforated cards, which rise accidently, sometimes on one side of a card, and sometimes on the other, in consequence of certain circumstances in the form of their substances or situations. In a single card, supported without touching others, while perforated by the passing fluid, the bur generally rises on both sides, as I once showed to Mr. Symmer at his house. I imagine that the hole is made by a fine thread of electric fluid passing, and augmented to a bigger thread at the time of the explosion, which, obliging the parts of a card to recede every way, condenses a part within the substance, and forces a part out on each side, because there is least resistance.

QUESTION III

When a flash of lightning happens to hit a flat piece of metal, the metal has sometimes been pierced with several holes, whose edges were turned some the one way and some the other, so that it has appeared to some philosophers that several streams of electrical fire had rushed in one way and some the opposite way. Such an effect of lightning has been published lately by Father Barletti.

ANSWER

This will be answered in my remarks on Mr. Barletti's book; which remarks, when finished, I will send you.

QUESTION IV

Though, from the very charging of the Leyden phial, it seems clear that the electrical fluid does in reality not prevade the substance of glass, yet it is still difficult to conceive how such a subtile fluid may be forced out from one side of a very thick pane of glass, by a similar quantity of electrical fire thrown upon the other surface, and yet that it does not pass through any substance of glass, however thin, without breaking it. Is there some other fact or illustration besides those to be found in your public writings, by which it may be made more obvious to our understanding that electrical fire does not enter at all the very substance of glass, and yet may force from the opposite surface an equal quantity; or that it really enters the pores of the glass without breaking it? Is

there any comparative illustration or example in nature by which it may be made clear that a fluid thrown upon one surface of any body may force out the same fluid from the other surface without passing through the substance?

ANSWER

That the electric fluid, by its repulsive nature, is capable of forcing portions of the same fluid out of bodies without entering them itself appears from this experiment. Approach an isolated body with a rubbed tube of glass, the side next the tube will then be electrized negatively, the opposite positively. If a pair of cork balls hang from that opposite side, the electrical fluid forced out of the body will appear in those balls, causing them to diverge. Touch that opposite side, and you thereby take away the positive electricity. Then remove the tube, and you leave the body all in a negative state. Hence it appears that the electric fluid appertaining to the glass tube did not enter the body, but retired with the tube, otherwise it would have supplied the body with the electricity it had lost.

With regard to powder magazines, my idea is that, to prevent the mischief which might be occasioned by the stones of their walls flying about in case of accidental explosion, they should be constructed in the ground; that the walls should be lined with lead, the floor lead, all a quarter of an inch thick and the joints well soldered; the cover copper, with a little scuttle to enter the whole, in the form of a canister for tea. If the edges of the cover-scuttle fall into a copper

channel containing mercury, not the smallest particle of air or moisture can enter to the powder, even though the walls stood in water or the whole was under water.

DXVII

TO THOMAS CUSHING

LONDON, 7 July, 1773.

SIR: I thank you for the pamphlets you have sent me, containing the controversy between the governor and the two Houses. I have distributed them where I thought they might be of use. He makes perhaps as much of his argument as it will bear, but has the misfortune of being on the weak side, and so is put to shifts and quibbles, and the use of much sophistry and artifice, to give plausibility to his reasonings. The Council and the Assembly have greatly the advantage in point of fairness, perspicuity, and force. His precedents of acts of Parliament binding the colonies, and our tacit consent to those acts, are all frivolous. Shall a guardian, who has imposed upon, cheated, and plundered a minor under his care, who was unable to prevent it, plead those impositions after his ward has discovered them, as precedents and authorities for continuing them. There have been precedents, time out of mind, for robbing on Hounslow Heath, but the highwayman who robbed there yesterday does nevertheless deserve hanging.

I am glad to see the resolves of the Virginia House

of Burgesses.' There are brave spirits among that people. I hope their proposal will be readily complied with by all the colonies. It is natural to suppose, as you do, that, if the oppressions continue, a congress may grow out of that correspondence. Nothing would more alarm our ministers; but, if the colonies agree to hold a congress, I do not see how it can be prevented.

The instruction relating to the exemption of the commissioners I imagine is withdrawn; perhaps the others also, relating to the agents, but of that I have heard nothing. I only wonder that the governor should make such a declaration of his readiness to comply with an intimation in acting contrary to any instructions, if he had not already, or did not soon expect a repeal of those instructions. I have not and shall never use your name on this or any similar occasion.

I note your directions relating to public and private letters, and shall not fail to observe them. At the same time I think all the correspondence should be in the Speaker's power to communicate such extracts only as he should think proper for the House. It is extremely embarrassing to an agent to write letters concerning his transactions with ministers, which letters he knows are to be read in the House, where there may be governor's spies, who carry away parts, or perhaps take copies, that are echoed back hither

The resolves, appointing a Committee of Correspondence, and requesting the legislatures of the other colonies to do the same, for the purpose of promoting concert of action, were passed on the 12th of March, 1773, by the other colonies. See the Resolves in Wirt's Life of Patrick Henry, 3d ed., p. 87.