I think with you that there cannot be the least Occasion for my explaining your Method of impregnating Water with fix’d Air to Messrs. Banks and Solander, as they were present and I suppose are as well acquainted with it as my self; however I shall readily do it if they think it necessary. I am glad you intend to improve and publish the Process.

You must go half an Inch farther with your Spark to exceed what I show’d here with my Philada Machine in 1758 to Lord Charles Cavendish and others, who judg’d them to be nine Inches. My Cushion was of Buckskin with a long damp Flap, and had a Wire from it thro’ the Window down to the Iron Rails in the Yard; the Conductor of Tin 4 feet long and about 4 Inches Diameter. So powerful a Machine had then never been seen in England before, as they were pleas’d to tell me. A Machine was made from mine for Mr. Symmer, and was afterwards in the Possession of Lord Morton. A more convenient Construction I have never since seen, except that of yours.

I intend soon to repeat Barletti’s Experiments, being provided with the Requisites, and shall let you know the Result.

I should be glad to see the French Translation of your Book. Can you conveniently lend it to me when you have perus’d it? I fancy it was translated at the Request of Abbé Nollet by a Friend and Disciple of his as I know there was one (whose Name I have forgotten,) that us’d to translate for him Extracts of English Electrical Books. The Abbe’s Machine was a very bad one, requiring three Persons to make the smallest Experiment, one to turn the great Wheel, and one to hold Hands on the Globe. And the Effect after all but weak. Delor had a similar one, and invited me to see him exhibit to the Duchess of Rochefoucault, but the Weather being a little warm, he could perform nothing, scarce obtaining a Spark. This Inconvenience must have occasioned their Making fewer Experiments, and of course his not being so easily convinced. M. Le Roy, however, got early possession of the Truth, and combated for it with Nollet; yet I think the Academy rather favoured the latter. Le Roy will I suppose now confute this Translator, for I have just seen a Letter of his to Mr. Magelhaens, thanking him for sending so excellent an Electric Machine to France; (it is one of the Plate ones) which he has improv’d so as to produce the positive and negative Electricities separately or together at the same time, de façon (says he) qu’on peut faire toutes les Experiences possibles sur l’une ou l’autre de ces deux Electricités. Enfin on etoit si eloigné de connoitre les Phenomenes de ces deux Electricités ici, faute de Machines commodes de les démontrer, que beaucoup des Gens ont été etonnés de voir avec quelle évidence ils etablessent la distinction de ces deux electricités. &c. This Letter is of the 5th Instant. My best Wishes attend you and yours. I am ever, with great Respect, my dear Friend, Yours most sincerely