86 On the Galvanic Current. 
recover it again at Wye, on the eastern shore of Maryland, where 
the iMfusorial stratum reappears with all its usual characteristic 
cies. © 
4, Silicified Polythalamia in Florida.—While passing from 
. Pilatka to Tampa Bay, in Florida, I collected at “ Piles’s New 
Place,” about furty miles west of Pilatka, large masses presenting 
all the mineralogical characters of flint. These occur in veins 
in masses of the white Orbitulite limestone which is common 
throughout this portion of Florida. Much of this flint is suf- 
ficiently translucent to be mounted in thin fragments coated with 
m for microscopic examination. By this means I detect- 
ed in it numerous silicified specimens of Orbitulina, Nummulina, 
Rotalia, Textilaria, &c. The siliceous arrow heads found in 
great abundance in Florida, often present a similar character, and 
are doubtless from the same formations. : 
5. Localities of Paludicella articulata, Allman.—This beauti- 
ful Bryozoan polyp appears to be common in the Highlands of 
New York, I have found it in considerable abundance in all the 
ponds near West Point, and also in ditches leading from a swamp 
near the Crows Nest. It occurs attached to various submerged 
objects, such as growing plants, bits of wood or stone, fallen 
leaves, é&c., over the surface of which it spreads in an irregular 
branching manner, sending up from each joint a beautiful animal 
flower, formed of tentacles covered with vibrating cilia. I have 
kept it by me for weeks and find it a charming object for micro- 
scopic study. A figure and description of it may be found in the 
London Physiological Journal, vol. i, p. 10 
. Circulation in Hydrocharis spongiosa.—This plant grows in i 
almost every wet place in the Southern states, where it is often : 
known by the name of “Colts foot ;” I recommend it.to southern 
microscopists as a beautiful object for the study of the circulation. 
The hairs covering its aquatic roots are as transparent as glass, 
and afford an admirable display of the currents, and also of re- 
volving cytoblasts, 
ss 
4 
f 
q 
Sl ORLA eae ase 
te es - 
Arr. IX.—On the time required to raise the Galvanic Current — 
to wuts maximum in Coiled Conductors, and its importance in 
= ee ; by Prof. Cas. G. Pace, M.D., Washing- 
ton, D. C. 
M. Pourter communicated to the French Academy in 1837, 
“ that he had established that a circuit of many thousand metres — 
in length, was traversed by the current in a space of time that 
did not amount to z5's5 of a second; and that in this very brief 
instant it was not simply a portion of the electricity that was 
