The ferrotype and how to make it - The Grian Press

THE GLASS ROOM. 37
wood. (A good description of such an apparatus
may be found in the ^^Philadelphia Photogra-
pher/' for August, 1871, page 269.) By the
use of these blinds, sunlight can be entirely ex-
cluded by setting them as we do the blincls out-
side the windows of our residences, so as to in-
tercept the sunlight and not to exclude diffused
light and air; they also serve the purpose of
shading the glass from the extreme heat of the
summer sun.
Heretofore, one great difficulty with top lights
has been the leakage ; indeed, it seemed to be
almost impossible to secure a perfectly water-
tight Glass Koom, until some ingenious person in
Philadelphia invented the sash, named after the
city where invented, of which the following dia-
j^ram shows an end view. The letter A shows
B