I have been considering Mr. Coldens experiment2 which we tried on Saturday last, and the appearances it affords seem not now so surprising, or indeed, curious, as I at first imagined. For the excited tube, you know, when opposed properly to the cork balls, attracts them a little: it must therefore electrify the balls plus, instead of minus: and not only the balls will be electrified plus, in some degree, but the threads by which they are suspended, together with the leaden covering of the vial. On bringing the excited tube nearer towards the balls they will be electrified plus to as great a degree as the tube, in such circumstances, is capable of doing it: and after that is effected, a repulsion will succeed between the balls and the tube: which must ever be the case when they are both equally electrified and by the same power.

I will endeavour to satisfy you that this is probably the fact by an experiment or two which are easily made when I see you next—in the meantime believe me Yours most affectionately