LETTERS ON SCIENTIFIC SUBJECTS. 



SIR CHARLES CAVENDISH TO JOHN PELL. 



[MS. Birch, Brit. Mus. 4278, fol. 134.] 



Wellingor, June 26, 1641. 



Sir,, I perceive oure business of making the perspective 

 glass proceeds not, and I knowe not well howe to help it, 

 unless there be some as good matter to make glass in some 

 other place to be bought, for it seemes that at Broadstreet 

 will not be had; I am not willing to trouble Sir Robert 

 Mansfeild about it, though I thinke he would not denie me. 

 Therefore, if you or Mr. Reaves can finde fitting matter for 

 us somewhere els, ye should doe me a greate favoure ; Broad- 

 street I suppose will be the best place to make the glass, when 

 ye have bought the stuff to make it of. I shall write to Mr. 

 Reaves to give us his help herein. I must againe thanke you 

 for your waie of ordering aequations, and doe desire that you 

 will proceed in your intended analyticall worcke, as your oc- 

 casions will give you leave. I desire to knowe if Mr. War- 

 ners analogicall worck goe on or not. And so wisshing you 

 all hapiness I remaine 



Your assured freind to serve you, 



CHARLES CAVENDYSSHE. 



If you knowe an easie and readie waie to measure the re- 

 fraction in water, you should doe me a favoure to let me knowe 

 it ; for I confess I knowe none. 



SIR CHARLES CAVENDISH TO JOHN PELL. 



[MS. Birch, Brit. Mus. 4278, fol. 136. Orig.] 



Wellingor, Julie 24, 1641. 



Worthie Sir, I am glad to heare you have got some glass ; 

 I hope it is good and fit for oure purpose, for I should be 

 unwilling that you and Mr. Reaves should bestowe your 

 paines upon course glass. When you have tried what the 

 refraction is in that glass I desire to knowe it, and allso howe 

 you like the glass. I have latelie received some propositions 

 out of France, some demonstrated and some riot, but I will 

 not divert you from the business you have in hand. I am 

 glad you have begun the analogiques, and hope allso that you 

 proceed in your owne analiticall worcke. And so wisshing 

 you all hapiness, I remaine 



Your assured freind to serve you, 



CHARLES CAVENDYSSHE. 



