THE REVIVAL OF SCIENCE 123 



gested to Newton, who "read it with delight," 

 the binomial theorem. In it 77 was evaluated, 

 and it must not be forgotten that to Wallis 

 we owe the symbol for infinity, oo. Living in 

 troublesome times, under many rulers, he con- 

 trived, not without some loss of popularity, to 

 remain on good terms with all. His services 

 were, indeed, indispensable to a succession of 

 governments, for he had a power of decipher- 

 ing which was almost miraculous. Cromwell, 

 who seems to have had a great respect for his 

 powers, appointed him Savilian Professor of 

 geometry at Oxford in 1649. 



Another mathematical ecclesiastic was Seth 

 Ward, bishop of Exeter and afterwards of 

 Salisbury. Ward was educated at Sidney 

 Sussex College and, in 1643, was chosen as 

 mathematical lecturer to the University at 

 Cambridge. But, like Wallis, he was ap- 

 pointed, and in the same year, to a Savilian 

 professorship, that of astronomy another 

 instance, not uncommon at the time, of men 

 educated at Cambridge but recognised and 

 promoted at Oxford. He took the place of the 

 ejected John Greaves, who magnanimously 



