ON MATHEMATICAL TABLES. 169 



manner, merely accumulates obstructions which obscure the truth, and ren- 

 ders more difficult the task of his successors, who will have to be at the 

 pains not only of doing the work again de novo, but also of correcting the 

 errors into which others have fallen through his imperfect accounts. 



Art. 9. With regard to the future Eeport on the subject of general tables 

 that has been mentioned more than once, and is intended to be supplemen- 

 tary to the foregoing, it may be stated that a number of additional tables 

 have already been described and will be included in it ; but the cooperation 

 of others in the matter is requested. Whether the descriptions in the Sup- 

 plement will resemble those in this Report will of course depend on the ex- 

 tent of the former, as, if the number of works described be large, it may be 

 necessary to practise some curtailment. 



It is requested also that notices of errors detected in the Eeport may be 

 sent to the reporter (see p. 12). 



Art. 10. Although, as already stated, this Report has no pretensions to 

 completeness, still any one who notices the non-appearance of names well 

 known in calculation (such as that of Legendre) is asked to read the con- 

 clusion of § 1, the list of articles in § 3, and enough of the introductory 

 matter in § 2 to comprehend clearly the spirit that has directed the selection 

 of works included, before coming to the conclusion that the omission was not 

 intentional. Books such as Legendre's ' Ponctions Elliptiques ' and Jacobi's 

 ' Canon Arithmeticus,' though forming separate publications, yet belong more 

 properly to a later portion of the Committee's work, as they are conclusive, 

 not subsidiary tables ; the former belongs to Division II., and the latter to 

 Division III. (see § 1, p. 4). 



It is perhaps worth noting explicitly, that the word Report has sometimes 

 been used to denote the whole Report that is contemplated by the Committee, 

 including 'the accounts of the Integral and Theory-of-Number tables, and 

 sometimes only the portion of it that will form one year's instalment ; but 

 the context always shows, without risk of confusion, the meaning to be 

 assigned. 



Art. 11. It was originally intended that the list in § 5 should merely con- 

 tain the titles of the books described in §§ 3 and 4, with references to the 

 section and article where each description was given. But it has been found 

 convenient to render it in addition more of an index to the whole Report by 

 adding cross references, and also a few titles of papers often referred to, as 

 well as references to the places where certain other works or tracts (besides 

 books of tables) were noticed. One or two remarks that should have appeared 

 in the accounts of the works themselves in §§ 3 and 4 have been added 

 after their titles in § 5 (see Babbage, Noeie, 1844, and Napier, 1619, in 



A table of contents is given at the conclusion of this postscript. Whether 

 a work of reference ever gets into use or not depends more on the complete- 

 ness with which it is indexed than on any thing else. 



Art. 12. The following statistics will not be found without interest. The 

 number of separate books of tables described at length in this Report (ex- 

 clusive of diiferent editions and of works only noticed incidentally) is 235, of 

 which only 5 are derived from second-hand sources. The 230 that have 

 thus come under the eye of the reporter are thus distributed among the dif- 

 ferent countries : — 



Great Britain and Ireland .... 109 France 27 



Germany (including Austria &c.) 66 Holland 8 



