Newton’s description of the reflecting telescope

In an earlier issue of Notes and Records , A. A. Mills and P.J. Turvey published a general account of the reflecting telescopes associated with Isaac Newton. There is another document concerning the reflecting telescope that has not until now been incorporated into the Newtonian literature: a schematic drawing of a reflecting telescope, accompanied by a description of the instrument written out by Newton in his own hand (see figure 1). The drawing was certainly made by Newton himself. At the bottom of the page, there is a note in another hand, of which the first part reads, ‘Ex dono celeberr. Dn. Newgtoni Profess. Math. Cantabrig.’ (the gift of the famous Mr Newton, Professor of Mathematics at Cambridge), and the remainder, in English, reads ‘of Cajus Colledg.’ This is, of course, an error, since Newton’s college was Trinity and not Caius; Newton’s name is also misspelled.