222 LeVerrier on the constitution of the Solar System. 
Art. XXIX.—On the constitution of the Planetary System: and 
on the theory and tables of Mars, (in a letter addressed to Marshal 
VAILLANT); by M. U.-J. LeEVerrrer, Director of the Obser- 
vatory of Paris.* 
Laying aside long formule and tedious calculations, immense 
series of observations and dry tables of numbers, in short, all 
professional apparatus, I will here speak only of the results of 
my labor so far as it relates to the physical constitution of our 
system. 
The existence of the bodies of our system is made known 
in the most simple manner, when we see them. There is reason 
to fear, however, that more than one of them may escape US, 1} 
erful optical apparatus. 
The planes of the orbits in which the planets move suffer 
: : the action 
changes, ascertained by observations, may serve to determine 
the weight of the bodies which produce them. ; : 
Further, were it to be supposed that the only disturbing 
masses were those of the known planets, it wou necessarily 
result that the variations of all the orbits would agree in givIDg 
* From Comptes Rendus de ? Acad. des Sciences, of June 3, 1861. 
ete 5 ee 
