LETTERS ON SCIENTIFIC SUBJECTS. 107 



and have methinks a prospect of methods that I hope will 

 not faile in the attainment, consisting of two branches. The 

 one to make such habitudes or co-efficients relating to two 

 tearmes in an equation, that taking away one of them, the 

 other shall vanish with it. The other to reduce such tearmes 

 to those habitudes that want them, though something hath 

 been done in this kind and not in vaine, yet there still is re- 

 quired more still labour and time, than can be affoarded by 

 his and 



Your most humble servitor, 



JOHN COLLINS. 



SIR SAMUEL MORLAND TO JOHN PELL. 



[MS. Birch, Brit. Mus. 4279, fol. 143, Orig.] 



Saturday, 13th May, 1682. 



Sir, Not being able to wayt on you as yet (as I intended) 

 I take the boldness to send you my first request in writing, 

 which is to beg you to answer the following queres : 



1. Supposing a foot to be divided into 12 inches, what is 

 the number (and decimal parts) of cubick inches which are 

 equal to the content of a cylinder, the diameter of whose base 

 is 1 inch, and the height 12 inches? 



2. What is the number of cubick inches that equal the 

 content of a cylinder, the diameter of whose base is 2 inches, 

 and the height 12 inches ? 



3. What is the number of cubick inches answering to a 

 cylinder, the diameter of the base being three inches, and the 

 height 12 inches? 



And if your leisure will permitt you, I would beg a table 

 giving the number of square inches conteyned in the areas of 

 all circles from 1 inch diameter, to a 100 inches diameter. 



And what trouble this shall give you, shall be acknow- 

 ledged by 



Your most humble and faithful servant, 



S. MORLAND. 



