OPPOSITION OF M. DE LAPLACE. 81 
ous comets, and calculated their orbits. I had, in concert 
with M. Bouvard, calculated, according to Laplace’s for- 
mula, the table of refraction which has been published in 
the Recueil des Tables of the Bureau of Longitude, and 
in the Connaissance des Temps. A research on the 
velocity of light, made with a prism placed before the 
object end of the telescope of the mural circle, had 
proved that the same tables of refraction might serve for 
the sun and all the stars. 
Finally, I had just terminated, under very difficult cir- 
cumstances, the grandest triangulation which had ever 
been achieved, to prolong the meridian line from France 
as far as the island of Formentera. 
M. de Laplace, without denying the importance and 
utility of these labours and these researches, saw in them 
nothing more than indications of promise ; M. Lagrange 
then said to him explicitly :— 
“Even you, M. de Laplace, when you entered the 
Academy, had done nothing brilliant; you only gave 
promise. Your grand discoveries did not come till after- 
wards.” 
Lagrange was the only man in Europe who could with 
authority address such an observation to him. 
M. de Laplace did not reply upon the ground of the 
personal question, but he added —*I maintain that it is 
useful to young savans to hold out the position of mem- 
ber of the Institute as a future recompense, to excite 
their zeal.” 
“ You resemble,” replied M. Hallé, “the driver of the 
hackney coach, who, to excite his horses to a gallop, tied 
a bundle of hay at the end of his carriage pole; the poor 
horses redoubled their efforts, and the bundle of hay 
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