Of GREATEST ATTRACTION. 243 
BC’ — EC’, therefore c= EC or BD. So alfo, c+ a= 
BD’ + BA* = AD*%, becaufe ABD is a right angle, &c. Thus, 
(AF+EN)AE | 
(AD + DE) (AN 
(AF + FM) AC 
(AD + DC) AM" 
Fo>=,a—7a4+BE. Log 
BC. Log 
Tuts expreffion for the attraction of a parallelepiped, though 
confiderably complex, is fymmetrical in fo remarkable a de- 
gree, that it will probably be found much more manageable, 
' in inveftigation, than might at firft be fuppofed. That it fhould 
be fomewhat complex, was to be expected, as the want of con- 
tinuity in the furface by which a folid is bounded, cannot but 
introduce a great variety of relations into the expreflion of its 
attractive force. The farther fimplification, however, of this 
_ theorem, and the application of it to other problems, are 
fubje@s on which the limits of the prefent paper will not 
permit us to enter. The determinations of certain maxima de- 
pend on it, fimilar to thofe already inveftigated. It points at 
the method of finding the figure, which a fluid, whether elaftic 
or unelaftic, would affume, if it furrounded a cubical or prifma- 
tic body by which it was attracted. It gives fome hopes of be- 
ing able to determine generally the attraction of folids bound- 
ed by any planes whatever ; fo that it may, fome time or other, 
be of ufe in the Theory of Chryftallization, if, indeed, that 
theory fhall ever be placed on its true bafis, and founded, not 
on an hypothefis purely Geometrical, or in fome meafure arbi- 
trary, but on the known Principles of Dynamicks. 
Vox. VL—P. IL. Hh Vv. 
