A problem from Descartes, worked through by Hudde, whose notes were included in the 1659 edition of the Geometria. This was probably written out in Rotterdam and sent to a friend as a letter.

Juxtaposed to this item, and possibly out of sequence, is the unlabelled and undated "Francisci Renati Slusii Methodus Tangentium', extracted in a hand other than Gregory's, from the January 1673 Transactions.