Descartes’ Copy of [Oct.-Dec. 1635, 
APPENDIX H* 
DESCARTES AND HUYGENS’ DISPUTE WITH 
SAUMAISE. 
w 
Descartes’ copy of Huygens’ reply to a 
LETTER OF SAUMAISE TO RlVET. 
[Oct.-Dec. 1639.] 
From the autograph in the Royal Library at the Hague. 
Three single sheets foolscap, each folded into two. Text on la and ib 
of sheet i ; la and ib of sheet z ; la, ib, za, and zb of sheet 3 j za and zb 
of sheet z ; and za of sheet 1. 
Saumaise’s letter in sections in the margin. 
The whole in Descartes’ hand except the two notes (Copie, etc. and 
TextuSy etc., 11. 1-7) which are in that of Huygens, the one in the left, the 
other in the right, top corner of 1a. 
For the circumstances of this Reply see XLVI, above,p. no, 
/. 8 6 n. It was asked for, and copied by Descartes in December 
1639 [above, XLVI,^. 111, //, 97-8 3 XLVII\p, 113,/. 39/3 
XLVIII,^. 117,11. 62-3 ), but the copy only reached Huygens in the 
middle 0/1*43 {above, LXXXII, p. 199, /. 20/; LXXXIV, 
p. 202,/. 9/j LXXXV,p. 208, /. 82/; LXXXVI,/ 213, 
/. 9sf', LXXXVII, p. 21*, /.47/3 XCIII 9 p. 228, /. 2/; 
and XCIV,/. 230, //. 2-4.) 
The manuscript was sold as lot 124 in the Sotheby sale of 1827 
æW was bought by Thorpe for £1 (.Introd1, above^p. xxxvi, n. 1). 
It came into the possession of the I{oyal Library at the Hague by 
purchase through M. Charavay in September 1916. 
Pages 1 a and lb of the manuscript are reproduced in facsimile by M. Cohen in 
Écrivains français, etc., plates XL.lIl-XL.lVy following p. yiz. 
* The documents which follow do not form part of Mr. Buxton’s col 
lection. 
For the transcripts from which they are published and for much of the 
information contained in the notes I am indebted to M. C. de Waard. 
310