2S og 
* 
W. P. Trowbridge on Deep Sea Soundings. 163 
In this latter expression (P) represents the weight of the body 
in air, including also the weight of the fluid drawn along by 
the body, and “0 the time in seconds. 
The velocity will increase as (¢) increases, and will become 
constant when the factor Wei becomes unity ; and it is evident 
pet when (¢) becomes so great that N may be taken for V—1 
+1, without sensible error, the velocity will have become 
auely constant, and will be represente 
Oa) A, Meme 
S.D.(m-+9) 
In the case under consideration g=382189 (feet), ideas? 38 
(pounds), the weight of a 82-pound iron shot in sea water, S= 
0:21 (square feet), D represents the weight of one ores foot of 
sea water =64:177 (pounds), and (m+gq) as determined by Du- 
buat in the experiments given in the “ Principe d’Hydraulique” 
for a sphere moving in water =0'5. These constants substituted 
> ad formula give for one 32-pound shot, falling freely in sea 
Tn 16- 21 (feet per second) for the maximum y ocity. 
To find the space —— over, before this neha is reached, 
we have this ee 
V+1 
=5.D ma 18 OW 
dete nay kn for N this expression may be placed 
under t 
oP 
lZ=35 3D ota <~(t i 29 W.SD wt gL. 2). 
The time which must elapse before N becomes so great that 
N+1 may be taken for it, may be determined from the expression 
L. N=5VI9W. S.D(m-+9). 
“aye oy 8 in this expression the values of the known quan- 
es for a 82-pound shot we have 
L.N=t. (313) 
For 1 second Z.N=3:13 and N>10; for 2 seconds L.N= 
10,000 see N=1000 nearly; for 3 secon ds L.N=9:39 and V= 
us at the end of the third second V becomes so great that 
terminin, 
N+1 may be taken for it, without sensible error, in determini 
‘Veloci d = the formula for the a gives for 
SY ecat t 1 sec. Z=9'11 feet, 2 sec. Z=25 
he and second seco 
& .° nearly, aa 1: 16°21 (feet) for each second afterwards. 
