FRANCIS WILLUGHBY. 67 



to Cirencester, but hearing by the way of a great 

 deal of treasure that was found in a field, I 

 presently conjectured that it might be a Roman 

 coin, and directed my course thither. The field 

 was near Dursly, a town we left about a mile of 

 the left hand as we rode from Glocester, where I 

 found above forty people digging and scraping, 

 and bought a great many silver medals of them, 

 and one incomparable fair one of gold that had 

 been found a little before. The whole history 

 how these came to be discovered I shall reserve 

 till I see you. I thought to have made strict 

 inquiry after the snap-apple bird, but falling very 

 sick at Malverne, I was forced to give all over." 

 There is also proof that Mr Willughby had, by 

 this time, made high attainments in mathematical 

 learning. In the Philosophical Letters there are 

 two addressed to him by Dr Barrow; the one 

 dated Trin. Coll. March 26, 1662, and the other, 

 October 5, 1665. 



In the first of these, Dr Barrow speaks of Mr 

 Willughby 's observations concerning " the spiral 

 line, as having sufficiently evinced the invalidity 

 of a supposed demonstration concerning its 

 equality with the semi-periphery." In the 

 second letter, he says, " Your discourse infer- 

 ring the solidity of the sphere from the surface, 

 by comparing the concentrical surfaces of the 

 sphere with the parallel circles of the cone, is very 

 ingenious and solid," &c. " Your observation 

 about the equality of the annuli, with spherical 

 portions, is also true and ingeniously proved/* 



