The New York herald., 1869-06-18
NEW YORK ASSOCIATION FOR IHE ADVANCE.
MEXT OF SUE .CE AND ART.

At the last meeting OF this association, an in
strument called bathometer was exhibited by the in
ven.ors and an explanation OF the method OF its
operations given. After setting forth the difficulties
encountered hitherto in the attempts TO sound the
sea ana the devices introduced to overcome them
description Of the instrument exhibited was given.
Its success depends uDon the new and inge-
nious method adopted TO secure the buOyancy OF
the plummet. This Indispensable quality is OBJ
tanned by the OF hollow glass balls three or four
inches In diameter, the glass having thickness of
about one-tenth of an inch, Of such lghtness to
float with half their surface above water, and sui-
Client strength. shown by actual test with hydrau-
lie press, to sustain pressure OF four ana half
tons TO the square inch In outward appearance the
plummet is simply q wooden cylinder with
rod a lew feet IN length rising from the
top and terminating in little FURNISHED
silver ball. To this Is hung a weight TO sink II,
attached by compound lever balanced by little
concal cuS attached to a string and dropping few
feet lower than the weight. This cup Is hung with
It's point downward, aud has over 1t, sliding on the
string, leather cover which Is raised as the cup
comes IN contact with any obstacle to its downward
course the baance between 1t and the weight Is
DESTROYED and the latter drops from the pnmmet
| its great buoyancy. bearing along with 1t the
when iss, nas dropped IN the sand w
its little leather cover at the moment
OF its commencement to rise. So much for the out
ward appearance OF the instrument which is
dropped into tine water, without any line to recover
it. and which is found when ii rises by OF the
brightness Of the silver ball. which rises few feet
above the water when the bathometer comes To The
surface. open this hollow, wooden cylinder ana it
Y N be found filed, twothrds OF its upper part with
the glass balls already described. and the bottom
with ballast TO keep the cylinder upr1gnt While III
the water Between the glass balls and the cylinder
is placed the bathometer proper This consists OF
glass bottle, with long, slender neck closed al the
top. The mouth OF the bottle may be
said to be at the bottom. This mouth IS
stopped with a stopper OF India rubber, through
which runs glass tube, having its upper
end i'm the bottle and the lower end in an India
rubber bag. The bottle flied with water; the bag
with mercury and water. When tie bottle and bag
are placed the bottom OF the the water In toe
bottle is compressed by the pressure on the bag and
the mercury takes the place OF the void resulting
from the compression. Nnen the instrument re-
turns TO the surface all that has TO be done TO
certain the depth 20 which IL has been Will be to
turn the bottle the other side up ut Is placed In the
wooden cylinder with Its long, closed neck upward
and the mercury settling INTO the neck, on which Is
marked scale WILL by its height, indicate, as IN a
thermometer q barometer the depth to which the
instrument sank as the amount OF compression Is u
sure index Of the depth Of the COMPRISING column
Of water