Newton op.cit., pp.
506, 507. CHAPTER XIV PROGRESS IN ELECTRICITY FROM GILBERT AND VON GUERICKE TO FRANKLIN (1) (p.
274).
A letter from M.Dufay, F.R.S.and of the Royal Academy of Sciences at Paris, etc., in the Phil.Trans.of the Royal Soc., vol. XXXVIII., pp.
258-265. (2) (p.