dr. Gregory's strictures on don Rodriguez. 253 



as to make the positive and negative errors equal, obtains T ^ T . Summary of 



Lalande, by comparing Father Leisganig's degrees in Germany staten,cnts ? 



with eight others in different latitudes, gets _^- T . And the 



recent measures in Fiance give, as we have seen, T ^-g.. Such 



is a summary of the evidence from which it is to be concluded 



that the earth is " elliptical," even " very regularly so." General 



Roy, who had got a habit, not very uncommon among scientific 



Englishmen, of deducing reasonable conclusions from anomalous aml (; enera i 



appearances, and not twisting them to suit a fanciful hypothesis ; Roy's deduc- 



assumed seven different spheroids of varying ratios between ^em. r ° 



-j-4-jj. and ^i^, and, on finding that none of them corresponded 



so uniformly as might be wished, with the operations in 



different latitudes, made these inferences : f Hence it is 



obvious, that the arcs of an ellipsoid, however great or small 



the degree of its oblateness may be, will not any way correspond 



with the measured portions of the surface of the earth." 



" Hence it is that philosophers are not yet agreed in opinion 



with regard to the figure of the earth j some contending, that 



it has no regular figure, that is, not such as would be generated 



by the revolution of a curve around its axis." And again, after 



specifying some other facts, " from all which we may conclude, 



that the earth is 720/ an ellipsoid." 



Nor is this opinion peculiar to General Roy, it is common, I 



believe, to all who have contemplated the subject, except Don 



Rodriguez. Thus, Puissant, at p. 187, °f his Geodesie, says _ . M 



. ■ .Puissant s 



" La comparaison des divers degres measures & l'equateur, en dednctioB* 



France,en Pensylvanie,etc.donnelieu a decider que les meridiens 



§ont differens entreux et n'ont pas la forme elliptique." And at 



p. 222. M D'on Ton doit conclure que la terre ria point la forme 



reguliere que Ton serait tente* de lue attribuer." To the same 



purpose writes Laplace, at p. 56 of his ft Exposition :" f Les Laplace's 



degies du nord et de France donnent ^\^ pour l'eHipticite de 



la terre, que les degres de France e*t de l'equateur, donnent 



egale a - 3 ±^ 5 il paroit done que la terre est sensiblement » - 



diffcrente d'un ellipsoide. II y a raerae lieu de croire qu'elle 



ti 'est pas un solide de revolution, et que ses deux hemispheres ne 



sont pas semblablesde chaqUecote de l'equateur. 



It is curious, however, to observe that, notwithstanding this 

 extreme want of uniformity, in the results furnished by terres- 

 trial 



