the mean Denfity of the Earth . 785 
firft experiment of the kind which has been fo minutely 
and circumftantially treated ; and firft attempts are fel- 
dom fo perfeft and juft as fucceeding endeavours after- 
wards render them. And, befides, a frequent repetition 
of the fame experiment, and a coincidence of refults, 
afford that firm dependance on the conclufions and fatif- 
faftion to the mind, which can fcarcely ever be had from 
a Angle trial, however carefully it may be executed. For 
thofe reafons it is to be wifhed, that the world may not 
reft fatisfied barely with what has been done in this in- 
ftance, but that they will repeat the experiment in other 
fituations, and in other countries, with all the care and 
precifion that it may be poflible to give to it, till an uni- 
formity of conclufions fhall be found, fufficient to efta- 
blifh the point in queftion beyond any reafonable poffi- 
bility of doubt. What has been already done in the pre- 
fent cafe will render any future repetition more eafy and 
perfect. But improvements may be made, perhaps both 
in the mode of computation and in the furvey ; in the 
latter, efpeciallv, there certainly may. Some improve- 
ments of this kind I have hinted at in fome parts of this 
paper, which with others 1 fhall here collect together, 
that they may readily be feen in one point of view. They 
are principally thefe. Procure one bafe, or more if con- 
venient, very accurately meafured, in fiich fituation, that 
Vol. L XVIII. 5 E as 
