From William Henly
ALS: American Philosophical Society
[After May 4, 1772]
Worthy Sir

I shall take it as a particular favour if you will be so obliging as to give the bearer leave to copy out for me the Account of the damage done by the powder Magazine which was fired by the Lightening-ever since you mention’d it to me I cannot get it out of my thoughts. I spoke of it to Mr. Nairne on Saturday, repeating what you observed to me concerning that at Erith, says he I really shudder at the thought. The more I think of Mr. Wilsons scheme for a Conductor the more I dislike it. If I understand the plan aright, it seems not at all unlikely that he would invite a stroke upon his Iron Bar in its full force, and as a Base of Brick work may in dry seasons be looked on as a kind of imperfect insulation, if the Electricity should not be properly dissipated at the bottom who can foresee the consiquence? Should mischief ensue from such an improper apparatus, it might contribute to bring them into disrepute, and so prevent the many good effects which may by proper management be always expected from them.

Mr. Nairne observes to me that the mark made by the spontaneous discharge of a positively charged bottle is only on the inside of the uncoated part of the glass-if the bottle be charged negatively the mark is on the outside only. I intend to try this soon with 2 new Bottles which I shall mark previously to my making the experiment, tis however perfectly consonant to all my experiments made on the surfaces of Glass Ivory &c.

I have written to Dr. Priestley and contradicted the Report of the House &c. in Jamaica. I am Sir faithfully yours

W Henly

Addressed: Dr. Franklin
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