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3
396
hit and miss Ventilator, and the
remain_
arrived out from England. apparaties, can arrive out
On the vertical axis of the light house and in the centre of the highest course which is
one 18 inches thick, a circular
The
coping
be
hole will be left 10 inches in diameter to receive the collar which holds the shaft of the apparatus . This hole can chipped to any larger diameter it on arrival the collar should be
to
into it.
e found
too
large to fit
3. It is desirable to leave to the Crown Agents the particular class of lenticular apparatus and construction of lantern to be selected, and the undersigned therefore will limit himself to a few appropriate
suggestions on The dimensions, and con-- struction of the light, room and it's acces-
sories.
4. As the lantern will nost
likely have
sixteen, sides it is recommended that the
light, room should be a sixteen sided polygon.
to be composed of of cast irow plates so as to form when lined inside
with wood, a circular chamber 12.
12 feet
in diameter; Fifteen plates to have each
a
a circular orifice
to be
furnished with
hit
}
-ing plate to be provided with a door lead- -ing from the light room to the outside
outside gallery balcony. A suitable iron hand rail - required for this outside
for this outside gallery.
of
5. The usual inner service gallery of
perforated cast now plates to
go round
the inside circumference of the lantern
iron
upon plates or walls. Iron steps leading up from the light room floor into the hunterns. The steps to be provided with a light suitable
brackets to be bolted to the vertical
handrail.
6 . Tole plate to fit on the top of the blocking. to be roughed and to project
and to project 12 inches so as
to form a path outside and round the Cautern for a
man to walk or stand upon the outside of the
a
while cleaning
sole plate will also form,
of the
: the glass. The
an lave to shelter
the light-room Ventilators against rain.
7.
"The height of the light room floor above
the mean sea level has been based on the - assumption, that the height of the focal plane, above it (the floor) would be 11 feet Cincher. It would therefore be desirable - if it can be done conveniently.
to adhere
to