192 Mr. T. T. Wilkinson on Mathematics and Mathematicians, 



dent that the velocities which bodies must have to rise to any 

 heights must be the same that the bodies would acquire, by fall- 

 ing through the versed sines of the arcs they describe. Conse- 

 quently for a ball suspended by a string to rise till it become 

 horizontal, it must have a velocity at its lowest point equal to 

 what it would acquire by falling through the length of the 

 string of suspension. 



*' September 4. I called on Major Watson, who was just going 

 out to Sion Hill to see Mr. Robinson, Lord North's Secretary, 

 and he asked me to go with him ; accordingly we went together 

 in a chaise, but he was not at home. We then went to Sir 

 Charles Frederick's, but he was also from home. We then went 

 to Pickett's at the Foundiy near Blackfriars Bridge, and to 

 Dr. Irwin's ; he who made salt-water fresh. I then went with 

 Major Watson home and dined with him. After six o'clock I 

 came to Mr. Todd's in Smithfield, and he and I went to see 

 Mr. Wales ; we stayed supper, and he showed us the weapons, 

 &c. from Otaheite and New Zealand. 



'' September 6. I called on Lord Charles Cavendish in the 

 forenoon. He suspected that some one had wished to deter me 

 from making calculations for him ; so after some conversation 

 I was to make out a Table of Aberrations for him ; to finish 

 the first Table about the Nutation and to calculate one month, 

 viz. December 1769. In my way home I called on Mr. Robert- 

 son, but he was not come out of the country, so I left the result 

 of the Eclipse with his daughter and dined there. On my 

 way home I met Mr. Atkinson in Fetter Lane, who told me the 

 Quaker was very well pleased with my solutions to his questions." 



Mr. George Sanderson was a "tailor in Doctors Commons," 

 a member and some time President of the Mathematical Society 

 of Spitalfields, which was established by Mr. Joseph Middleton 

 in 1717. He was one of the ablest geometers of the period, and 

 his contributions to the Diaries and the London Magazine are 

 both numerous and important. Whether there was an eclipse 

 at the time mentioned by Herodotus appears to be still undeter- 

 mined. The subject has been considered by some of our ablest 

 astronomers, but their results are not conclusive. I have not 

 been able to meet with Dr. Priestley's statements, on the autho- 

 rity of Mr. Burrow, nor is the nature of his conclusions anywhere 

 stated in his journals : — an interesting summary of the principal 

 results may be seen under the article 'Alyattes ' in the first volume 

 of the Penny Cyclopaedia. Neither the Journals nor the Diary 

 contains any further notice of the new edition of Simpson's 

 Fluxions ; hence the probability is that Mr. Robertson was either 

 unsuccessful in his application to Nourse, or that the edition was 

 abandoned. The solutions of the Quaker's questions appear 



