TRIGONOMETRICAL SURVEY OF INDIA. 193 



that an increase of density in the earth, from the surface to the centre, 

 would be attended with a greater protuberance at the equator than in the 

 cases of homogeneity. 



As it is not an object to enter into a minute investigation of this 

 abstruse question at present, tliis part of the subject may be dismissed 

 with the name of M. Clairaut, who first fully considered the question of 

 the figure which a planet must assume with a density gradually increasing 

 from the surface towards the centre. 



The theory of Sir Isaac Newton was not well received at first — it 

 impugned the doctrine of the vortices of Descartes, which was then in 

 high favor in France. M. Picard had measured an arc of the meridian in 

 France between Amiens and Malvoisine about 1°^ of the quadrant; 

 MM. Cassine, De la Hire, and others, resumed this, and continued it 

 through the whole extent of France in several sections, which were finish- 

 ed in 1718, and it was found that the lengths of the degrees diminished as 

 the latitudes encreased, which ratlier tended to give an elongated than an 

 oblate form to the globe. Tiiis was afterwards found to result from errors 

 of computation, but since the comparison of contiguous degrees is not the 

 best way to determine with great accuracy so very small a quantity, as 

 the compression would be, the Government of Louis XV. resolved on 

 fitting out two expeditions, one of which should measure an arc as near 

 the equator and the other as near the pole as possible. 



It was in 1735 that MM. Bouguer, De la Condamine, Godin, and 

 several assistants and artists on the part of the French GovernuKMit, ar- 

 companied by Dons J uan and Ulloa, on the part of thai of Spain, wiwl to 

 Quito, in Spanish America, and at the sani(> liiiu- the northern expedition 

 under MM. Maui'Ertuis, Clairaut, Mounh.k, Camus, Celsii's, and 



3 15 



