Mr. T. S. Davies on Geometry and Geometers, 205 



taining a statement of accounts, Nov. 22, 1777.) He asked 

 thirty guineas, and estimated it at seventeen or eighteen sheets ; 

 see letter, Sept. 26, 1776. Fluxions were cheap then, but 

 they command no price at all now. 



It may be worth noticing, that Dealtry's is the last book 

 published with the name and notation of Fluxions in this 

 country ; but Jephson's the last with the name only, having 

 the notation of Leibnitz instead of Newton's ; the former in 

 two successive editions, and the latter in two volumes issued 

 at different times. The eleventh edition of Hutton's Course 

 is, however, the last English book in which either the 

 name or notation appeared (1835, 1837); and though I 

 strongly urged upon Dr. Gregory, who acted as principal 

 editor of that edition, the necessity for a change, I failed to 

 convince him. This was the more inexplicable to me, as he 

 had for many years admitted the language and notation of the 

 Differential Calculus (though, perhaps, not its metaphysics) 

 into the Ladies' Diary, of which he was the editor. It first 

 appears in 1824 in the Diary*. His argument for retaining 

 it in Hutton's Course was, that Dr. Hutton himself would 

 have insisted on its retention ; and he felt himself bound in 

 honour to make no further changes in that work than the 

 author himself would have made under the same circum- 

 stances, and with a full knowledge of the state of mathematical 

 science in 1836. As I am personally interested in this ques- 

 tion, I may be allowed to state that I consider that view to 

 have been a mistaken one; and that a resolute adherence to 

 what it was supposed Dr. Hutton would have done, has driven 

 the work " out of the market." The ultimate changes made 

 in it came too late; and yet no man was more eminently qua- 

 lified to make them than Dr. Gregory. 



It appears from letters written in 1811 to Wingrave (suc- 

 cessor to Nourse) by Miss Maskelyne, that the Greenwich ob- 

 servations were the private property of* Dr. Maskelyne. They 

 are claimed as such; and Sir Joseph Banks's authority is 

 quoted in support of it. Yet the Board of Admiralty paid 



* See two interesting papers on the Introduction of the Notation of the 

 Differential Calculus into this Country by an eminent anonyme^ and by Mr. 

 Wilkinson, in the Mechanics' Magazine for 1849. It may, however, be 

 remarked, that Dr. Gregory introduced the differential notation into his 

 Trigonometry (using the S instead of the d) as far back as 1816 ; and that 

 to the edition of Hutton's Course of (vol. ii.) 1837, he gave a translation, 

 literally, of a portion of Lubbe's treatise. I am not able at this moment to 

 give the dates of either Dealtry's or Jephson's works; but the former 

 ranged somewhere from 1812 to 1814, and the latter a little before and 

 after 1820. 



