On the Depth and Saliness of the Ocean. 43 
bottom ; the great difficulty which seems to present itself, is the 
preservation of the charge of the shell from damage by the enor- 
mous <smeag to which it would be ra st in its descent : such 
equator there is a depression to nearly the 5th parallel of south 
latitude, where a ridge occurs; at the 15th parallel we find ~ 
depression; 10° farther south we have another ridge ; 
again deepens and rises twice towards the polar circle. T i 
are it is true but conjectures derived from detached and isolated 
trials, and may not be confirmed by future and well conducted 
oeeeents; they are only adduced here to show the field open to 
Pihusetts even with the imperfect means we now have, could 
wi fail to make us scquinted with the submarine valleys and 
by the commanders of our men-of-war, that might beta n ad- 
vantage of whilst proceeding to and returning from the different 
foreign stations ; and I make no doubt that these would be readily 
authorized by the distinguished gentleman who now presides over 
th > naval service. All that is required is for this Association to 
some measures to forward this subject, and to point out po- 
Sitions at which it would be. most desirable to obtain results. . If 
those who have the direction of foreign navies could be induc 
to join, we should be enabled in a very few years to e 
complete sections of me oceans and seas, and full ingestigsnnt 
into the phenomena connected with the ocean. 
tele the sitio depth of the ocean: has not yet been suc 
cessfully determined, the numerous trials have resulted in deter. 
mining satisfactorily | its mean temperature and ay li niaband 
ee is sicoaaate 39°°5,* and nacorng? to Capt. wm exper: 
“Tam aware that several distin thers have reported dif- 
meh navigators and others ha p 
pa Uresalts ; among them Mr. i ven i ni it down to 36° and 37°, which 
erie mye met “eng ae the seers at sale 1000 Grape. ns } our own 
submarine currents. 
at so low a te fs tre wil on be cena 
3 through the 
