——aeee 
IMPROVEMENTS IN PHAROLOGY. 169 
cient are, that it should keep upright and be free from 
any oscillation such as is experienced by ordinary vessels. 
The means whereby I propose to attain this desideratum 
will, I think, be readily understood on inspection of the 
accompanying plate, in which all details are purposely 
omitted to avoid confusion. I propose entirely to change 
the form of the vessel, making that portion of it which 
is immersed hemispherical, and that which is above water 
the frustrum of an inverted cone; as I think that this 
form of float will present less resistance than any other 
to the action of the wind and waves where these are ex- 
pected to act from every point; although it may be advi- 
sable in certain situations to employ a vessel pointed to 
both ends. Through the centre of the float I propose 
to pass a cylindrical tube B (Fig. 1), the lower end of 
which shall project through the bottom of the float so 
as to form a hollow keel for the reception of ballast. 
That portion of the tube which is above the deck of the 
float serves as a tower upon which to mount the light, 
and may be divided into rooms for the accommodation of 
the light-keepers, &c. C is the lantern, similar to those 
of shore lighthouses, and D the gallery surrounding the 
lantern. I propose to employ a dioptric light apparatus 
of the second order, shown at EB, forty-five feet above 
the water, which will permit the light to be seen at a dis- 
tance of nine miles. F is a fly-wheel, or gyrator, mounted 
on gimbols placed a little above the centre of gravity of 
the light apparatus and fly-wheel taken together. This 
fly-wheel is placed on the upper end of the shaft G, which 
receives motion through the wheels H, I and J and the 
shaft K, from an engine or pair of engines placed on the 
third deck of the float; or the fly-wheel may be kept in 
motion at its proper speed by two relays, each of three 
meu. 
MM (Fig. 3) are small high-pressure steam boilers for 
