1878.] Addition to Mr Glaishers paper on factor tables. 229 



The list of factor tables given in § 3 (pp. 103 — 104) is of 

 course not complete ; and the smaller tables were intentionally 

 omitted from it. It is worth while, however, on account of its 

 early date, to refer to Cataldi's Trattato di numeri perfetti, 

 Bologna, 1603, of which Libri^ says "ce qu'il y a de plus curieux 

 dans I'ouvrage de Cataldi, c'est une table de diviseurs des nombres 

 jusqu'a 1000." I have not seen Cataldi's work, nor has Professor 

 Cantor, of Heidelberg, to whom I am indebted for the reference 

 to Libri. 



I may here correct an erratum in the specimen of a factor 

 table on p. 100, caused by a o being out of its place, viz. above 5 

 there should be a blank instead of 5, and above 10 there should 

 be 2, 5 instead of 2 only. 



The first fourteen printed pages of the factor table for the 

 fourth million were exhibited at the meeting of the Society on 

 October 28, 1878. 



^ Histoire des sciences mafhematiques en Italic, t. iv. p. 91. 



