74 LETTERS ON SCIENTIFIC SUBJECTS. 



SIR CHARLES CAVENDISH TO JOHN PELL. 



[MS. Birch, Brit. Mus. 4278, fol. 139. Orig.] 



Wellingor, November 20th, 1641. 



Worthie Sir, I hope Mr. Reaves is in a good forwardness 

 with the convex glass ; 1 dout not but you will trie all con- 

 clusions with it, which may conduce to informe you whether 

 it be an hyperbole or no ; as allso what proportion the dia- 

 meter of the glass hath to the line of the contracted beames 

 of the sun at the pointes of concourse ; as allso to observe 

 what aparances are made, the eye being placed in, before, or 

 behinde, the pointe of concourse ; and in the mean time, be- 

 fore the concave glass be made, to trie whether rny concave 

 glass which you have, will in anie sort fit it. Sir, I leave the 

 further scrutinie of this to your better consideration, and 

 wisshing you all hapiness, remaine 



Your assured freind to serve you, 



CHARLES CAVENDYSSHE. 



I praye you comend me to Mr. Reaves when you see him. 



SIR CHARLES CAVENDISH TO JOHN PELL. 



[MS. Birch, Brit. Mus. 4278, fol. 141. Orig.] 



Wellingor, December 18, 1641. 



Worthie Sir, I thanke you for your letter of December 13. 

 I am glad Mr. Reeves is so well fitted for oure worcke ; when 

 he hath done it, I dout not but you will make all such trialls 

 as maye give you satisfaction whether it be a true hyperbole 

 or not, and then proceed to the making of the concave glass ; 

 if this fit it not, I shall still be in hope that a concave on both 

 sides will. I have not (to my remembrance) scene Henis- 

 chius arithmetick, nor should desire, for his mislike of de- 

 monstration by letters ; yet if you thinke there be anie thinge 

 in him considerable, which is not in Vieta or de Cartes, I de- 

 sire you will send it me, and Mr. Moselei will paye for it, as 

 allso for Schemer's Ars Nova Delineandi. I confess I expect 

 not an exact booke of analiticks till you perfect yours. And 

 so wisshing you all hapiness I rest 



Your assured freind to serve you, 



CHARLES CAVENDYSSHE. 



