There are other copies at CUL MSS Dd.6.46 Dd.12.33 and Add. 2640. The first of these has the additional title 'Contracta Renati Des Cartesii Feltoneana', which seems to imply the authorship of one Felton, possibly John Felton (d. 1667), Fellow of Caius and usher of the Perse School. Dd.6.46 and Add. 2640 both belonged, like the present copy, to Cambridge undergraduates at the dates of copying, respectively 1688 and 1681. Dd.12.33 is roughly contemporary.