Bertelli--whose afore-named memoir we must confine ourselves to, as it is more satisfactory than are the accounts elsewhere given--makes mention that he has had in his possession, by courtesy of Sig. Giuseppe Valentinelli, the Royal Librarian of the Marciana at Venice, copy of a manuscript (Cod. CXXIX, classe 2, MS. Ital.) containing a brief comparison of Sarpi’s magnetic researches with those of Musschenbroek. This manuscript is again alluded to by Bertelli (Memor., p. 88) wherein it is said that lines 5–38 of the first column, p. 170, are headed “Observations of F.P.S. on the loadstone, collated with P. Musschenbroek’s Researches,” and embrace five paragraphs translated as follows: 1. The author had first tried the action of one magnet on another without entering into the question of calculation, but modern authors have, in view of the observations made, endeavoured to discover a method of computing magnetic forces in any proportion to the distances, and in the same better regulated systems they have discovered the cause to be uncertain (or varying) owing to the contemporaneous action of magnetic repulsion. 2. He was acquainted with the well-known action of the magnet on iron, but he understood--as even at this day some understand--that it was caused by the atmosphere. New experiments have made us seriously doubt this. He did not pay attention to the proportion of the magnetic forces as compared with the distances of iron, to the discovery of which the efforts of present philosophers are directed but in vain. He saw, however, that the facility or difficulty of attraction depends upon the size of the iron (maximum and minimum). 3. He was not ignorant of the direction of the magnet and of iron rubbed with the magnet towards certain quarters of the sky when he mentions the new discovery of the poles in the magnet, and the variation of the magnetized needle, from the Northern or the Southern quarters, but he did not know a greater number than two poles found in the magnet, the variation of the declination, or, I should rather say, the uncertainty of the variation and the different inclinations of the needle at different places on the earth. 4. Almost all the experiments referred to by Academies, with reference to the action of one piece of iron on another piece of iron, magnetized and not magnetized, and with regard to the changes of forces which arise from the various inflections of iron, have been sufficiently sketched out by F. P. S.