= - 
Miscellaneous Intelligence. 441 
“Velocity of | Velocity nail nator 
Values: sh p in feet |shipin knots La whan Distal sewenrntas ship, the pein a “the ut the 
of a. | per seconds. |per hour. tuken jft. per — te = wo Banna th bot- 
lowe values oft. 
10°; 16°18 971 5:7 2° 7 0 
20 8°02 4°81 | 2°02 2°74 2D 0 
30 5°26 3:16 | 2:00 2:68 2D 0 
40 3°85 231 1°56 2°48 2D 0 
50 2:96 1:78 | 1:30 2°27 2D 0 
60 2°31 1:39 ' 1.15 2°00 2D 0 
—The slip is obviously Vversa in feet per second, givin nee (as 
ig a 
bons ‘be afterwards shown) of ’012 (6Vversa)'* pounds per sien or er hd 
unds on the whole, which ret in strictness to subtracted from 
the eat of D, but which is too small a quantity to be noticed in practice, at least 
any cable similar to this. 
Now, taking the Seg depth of the sea to which the cable in Fey s 
tion is to be exposed at 2000 fathoms, and each fathom to weig 
water 6X Aes _ lb., say 2 Ibs. per fat , we have 4000 lbs. for the 
strain on the e, whatever may be the pope of the Rend or as the 
cable is said to 0 rea with about. 4} tons or 9500 bs., the greatest ed 
ow this resis roi. not exactly as the square of the velocity, nor is 
it indeed exactly as the diameter of the ca 
Upon the whole, I consider from a Yasar experiments, princi- 
pally those of Colonel Beaufoy, that when the eee in knots per hour 
is v, the resistance in seeue per fathom will, for the cable here supposed, 
be ee. enough represented by -012v1°*. 
sake of revity T shall take only the example of this cable at 
an ale of 20°, where the gy we we see, 4°8 knots per hour. N. ee 
taking the depth of the sea at 0 fathoms, we have L=D cose 
2000 XK 2°92—=5840 fat 
Taking, for example, <a ‘slipping bestia & of the a equal to the 
y le 
velocity of the ship, or paying out twice the necessary length of cable, 
we find for a slipping velocity of 4°8 pe so a hour, a resistance of about 
Ib. per fathom 
r the total slippin ce of the cable 1168 Jbs., 
by which amount ‘che strain on the ee at it the he ship’ s stern will be reduced, 
or the greatest strain will be se as Ibs., or to reduce 
half the cable. A a waste of one e knot of cable per hour, or a little 
more 20 ss cage it of the cable, would only reduce the strain about 
70 Ibs. 
From the above, it appears that we are not able materially to reduce 
the strain upon the cable without occasioning excessive waste, unless at 
‘Leviathan 
eS if, on the other hand, we increased the tension of the cable beyond 
that due to the simple cept of the sea, the cable would form a curve 
— 
—NOV., 1858. 
