4.08 Zach on lUpeating Circles. 



did not hesitate to attribute to the attraction of a Httle hill, the 

 summit of which was 630 feet above the level of the sea. 



This is the real object of the experiment which we under- 

 took and executed in the summer of the year 1810, and which 

 we gave to the public, in all its details, in a work published at 

 Aviwnon in 1814, under the following title: " U Attraction des 

 Montagues ct ses Effets siir les Fils-d-plomb, on sur les niveaux 

 des instrumens d'astronomie, constates et determines par des ob- 

 servations astronomiqiies et geodesiques faites en 1810 a Uermi- 

 tage de Notre-Dame des Anges sur le mont de Mimet, et an 

 fanal de Vile de Plaiiier, pres de Marseille, S7iivis de la descrip- 

 tion geometrique de la ville de Marseille, et de son territoire," 

 2 vols. 8vo. 



What was our surprise on finding that, in a work which ap- 

 peared in London in 1822, a celebrated English artist says in 

 a paper upon, or rather against, repeating circles : "A cele- 

 brated astronomer, a few years ago, in the south of Europe, 

 made observations for finding the attraction of a mountain 

 with a small instrument of the construction R ; and obtained a 

 deflection of the level equal to two seconds ; and, although his 

 telescope could not have been more than 15 inches long, from 

 this experiment brought out a density of the earth nearly co- 

 inciding with the Schehallien experhuent, and with the more 

 recent one which Cavendish obtained by direct attraction." 



We had, at first, some difficulty in recognising ourselves in 

 this account ; it was not till after we had read it again and 

 again, that we at length discovered two things; 1st, that this 

 celebrated artist meant to point us out in his excellent paper ; 

 2nd, that he had never read (at least with attention) the work 

 of which he speaks, and in which he makes us do and say what 

 we never did or said ; in which we had, on the conti'ary, done 

 and said the very reverse of what he attributes to us. 



As an apology for this estimable artist, it has been repre- 

 sented to us that he does not understand French : and con- 

 sequently that, as our work was written in that language, he 

 could not have comprehended it. This is a slight misfortune 

 which we will set right in a very few words. This great artist 

 makes us determine the density of the earth. Now the truth 

 is, that we never thought of doing it, that we never attempted 

 to do it, nor did we ever express the least wish to make any 

 such observation. We knew veiy well diat, to effect that, we 

 must have made the plan, the profile, the elevation, and all 

 the dimensions of Mont Mimet, in order to calculate its mass, 

 its capacity, and its distance fi'om our point of observation, 

 as Dr. Maskelyne did at Schehallien. Now this is what we 

 never wished to undertake, and what we never did under- 

 take. 



