DEN 
For the method of computing the denfity oe the earth 
from thefe data, we thall give the author’s own 
“T fhall firft compute i on the feepoAtion that the 
arm a s have weight, and that the weights 
exert no fenfible atradion, except on the neareft ball, and 
fhall then examine what correétions are neceilary on account 
of the arm and rods, and eae other {mall caufes. 
“ The fir thing is to find the force required to draw the 
arm afide, which, as was before faid, is to be determined by 
the time of a vibrati 
«The diftance i" ue centres of the two balls from each 
other is 73.3 inches, and therefore the diftance of each from 
the c centre of motion is 36.65, and the a of a pendulum 
Therefore if the 
fame time as a pendulum whofe length is ie S65 inches, that 
30-63 feconds; and therefore if the ftiffnefs of the 
igin 
wire is fuch as to make it vibrate in N feconds, the force 
which muft be applied to each ball, in order to draw it afide 
by the aes is to the weight of the ball as the arc of 
Ax NE x 3° 65 
* 39. 14 
end oft Ne arm is 38.3 inches from the centre of motion, and 
each divifion is =i,th a an _ and therefore fubtends an 
angle at the centre, w $ tz; and therefore the force 
which muft be apeled | to en ball, to draw me arm Hes by 
tothe radius. But the ivory {cale at the 
36.65 
one divifion, is to the weight of the ball as -——~ eee a to 
I, OY, as to I. 
I 
818N? 
ek of th 
the weights are approached to the balls, their centres are 
8.85 inches from the middle line of the cafe; but through 
inadvertence, the diftance from each other of the rods which 
of th 
8. 
36 ce to the chord of the — whofe fine is SiGe? OF 
in the triplicate ratio ei the ou iss half this angle to the 
/~ or in the ratio 
10.64 X .9779 X ga_| to Te The mean diameter of the 
earth 1s 41800000 feev and aad ‘ an mean denfity of 
the earth is to that of water fe attraCtion of 
the leaden weight on the ball will ‘. o that of the earth 
Vou 
DEN 
thereon, as 10.64 x .9779 X sl to 41800000 Ds: 
to 8739000 D. 
It is hee wn therefore, that the force which muft be ap- 
plied to each ball, in order sa draw the arm one divifion out 
of the weight of the ball; 
fits natura! pofition, is 
of its n p n,i aa 
and if the mean denfity of the earth is to that of water, 
as D to 1, the attraction of the weight on the ball is 
Syp000D of the weight of that ball: and therefore 
the attraction will be able to draw the arm out’of its na- 
tural pofition by pereenv oF 5668s D divifions : and 
therefore, if on mo oving the weights foal the midway toa 
near pofition, the arm is found to move B divifions, or if 
it moves 2 B divifions, on moving the weights from one near 
pofition to the other, it follows that the denfity of the carth, 
a ey VF 
feed B 
The maining part of the paper of Mr. Cavendifh is 
filled ois the calculations neceflary to find the correc- 
tions which are added to the table of experiments. 
Thefe being applied, and a mean taken of all the expe 
riments, the author concludes the mean eens of the 
earth to be 5.48 times greater than that of wa 
AL, Denratis, from dens, a cate is pled to 
certain ata in the pronunciation whereof the teeth have 
a principa 
Grammaria a and e{pecially the Hebrew ones, diftinguifh 
the letters into dental; labial, guttural, lingual, palata” &e. 
ENT S rm whi on been ap- 
or D, is 
r form oe 
di ided cavity open at both ends. 
Specics. 
Exverpuxantinum. Shell with ten ribs, flightly curved 
ay aed Linn.—Denticulus elephanti, Rumpf.—Dentalis, 
‘Tohabits the Indian and European feas, and is about four 
inches long ; the fhell is deeply grooved, green with the tip 
white. 
Shell with ten ribs, flightly incurved and 
Native of the fame feas as the former, and is by fome con- 
fidered as a varie 
ARCUATUM. Shell ribbed, curved, fubulate, and of one 
Country unknown; colour greeni 
Shell aes eight ‘ribs and eight rie 5 : 
tip acute, pe and tipped with white. Mart. Native of 
the Sicilian fea 
Sexancutum. Shell with fix ribs and ftriated. Schroet. 
Difcovered in a foffil ftate at Loretto. 
Denrauis. Shell with twenty ftriz, flightly curved and 
interrupted. 
Found in the Mediterranean, and is fometimes red, or 
reddifh at the ti 
Shell be dig jth ae continued and 
{mooth. ono . Shells, Native of Ee 
ropean ae about an ee a nd half in len gth. 
‘Agistinum, Shellreund, curved, continued, and fmooth. 
Miill, 
3K Inhabita 
