[ 2 7 6 ] 
XIX. On the mean density of the Earth. By Dr. Charles 
Hutton, F. R. S. 
Read April 5, 1821. 
A lthough the determination of the mean density of the 
whole terraqueous globe of our planet, is admitted to be a 
problem of the utmost importance to several branches of 
philosophy, particularly to physical astronomy, and the figure 
and constitution of the earth ; it would seem, from the dis- 
cordancy of the declared opinions of some eminent philoso- 
phers, that the problem is still in an uncertain state. Since 
the first notice of this subject by Newton, in his admirable 
Principia, it has often been incidentally alluded to, without 
receiving a precise determination ; with the exception of 
two instances only, in which it has been stated to be, cer- 
tainly or approximately, determined by experiment; namely, 
in the case of the Schehallien experiment, by Dr. Maske- 
lyne and myself, and by the Honorable Henry Cavendish, 
by a method invented by Mr. Michell. 
The former of these experiments was made by Dr. Mas- 
kelyne, in the years 3774, 1775, and 3776, by means of 
that large mountain in Scotland, in measuring its dimensions, 
and in comparing its attraction on a plummet, with that of 
the whole earth on the same ; the calculations on it having 
been made by myself, and first published in the Philoso- 
phical Transactions of the year 1778; and since more cor- 
rectly in the second volume of my Mathematical Tracts. 
