368 Dr. Herschel on the 
yet be had, the trifling inaccuracy thence arifing may well be 
excufed, till, at fome future opportunity, we may be per- 
mitted to repeat thefe calculations in a more rigorous manner. 
As we are now upon the fubject of fucli parts of the theory 
of planets as may be determined by calculation, it will not be 
amifs to fee how the quantity of matter and denfity of our 
new planet will fiand, when compared with the tables that 
have been given of the fame in the other planets ; and in 
order to this, let us admit the following data as a foundation 
for our computation. 
The parallax of the fun 8 
The parallax of the moon 57' 11 ", 
Its fidereal revolution round the earth 27 d. 7 h. 43' 1 1 // ,6. 
The mean difiance of the Georgian planet from the fun 
19,08 1 8. 
The mean difiance of its fecond fatellite from the planet 
The periodical time of this fatellite 13b. 1 1 d. 5' i // ,$. 
Hence we find, that a fpeflator, removed to the mean dif- 
tance of the Georgian planet from the earth, would fee the 
radius of the moon’s orbit under an angle of 27", 1866; and 
if 1, d, t, reprefent the quantity of matter in the earth, the 
difiance of the moon, and its periodical time ; M, D, T, be 
made to fiand for the fame things in our new planet and 
its fecond fatellite, we obtain, by known principles, M = 
^3. And, confequently, the quantity of matter in the 
Georgian planet is to that contained in the earth as 17,740612 
to 1. 
In order to caculate the denfity, I compare the mean of the 
four bright meafures of the planet’s diameter 3/ 7975 to the 
2 
mean 
