1871.] 
GLASS GARDENS. 
45 
temperature would be midway between the two. Now, glass walls, and especially 
glass gardens, dispense with the ice. Each, transparent wall transmits and 
becomes a source of heat to the next, and so on throughout the entire series. 
This grouping of these transparencies together is like receiving compound 
interest for our money. The sun is the inexhaustible bank we draw upon for 
heat. Ify the help of glass and the great commercial code for money-making,— 
small profits and quick returns,—this heat passes through our screens with great 
rapidity; enough caloric is, however, sifted out in its passage to raise the 
temperature of our walls sufficiently for our purpose, and the remainder is passed 
on to the next wall, and then to the next, and so on through the entire series. In 
opaque walls this warmth would have been buried or absorbed by the dead 
matter of which they were formed. But here it runs from wall to wall, and 
heats the whole. And these walls not only take, but give. Part of the caloric 
is reflected back, and part is sent down to warm the earth. The result of this 
reciprocal action and reaction, this emission and rebound of caloric is that 
the wall atmosphere in glass gardens is generally several degrees higher than the 
south side of a brick wall, at from 1 in. to 2 in. from its surface—the ther¬ 
mometers being placed at the same distance in both cases. Of course, did the 
mercury touch the bricks, the result would be different. But the practical fact 
of vital import is that the wall atmosphere, the very spot which the trees occupy 
on walls of every kind, is equal or superior in the glass gardens to what it is on 
the south side of brick walls. 
But what about the night temperature ? Everything that is satisfactory. It 
averages about the same as on the south side of brick walls. This, at first, 
surprised me; but considering that in glass gardens we have dispensed with 
refrigerating north borders, and north sides of walls, and that the whole surface 
of the wall and the entire area of the ground between is all south wall and south 
border, we see at once good practical reasons for this superior night temperature. 
Slowly, it may be, but sorely, the heat stored in the ground from the sun’s rays 
by day will be liberated at night, to check or counteract the radiation of heat 
into the open sky, and thus keep up the temperature of the glass garden. 
It only remains to give a few sketches of ground-plans and elevations of these 
gardens. The great points are to get in all the heat possible and to shut out the 
cold, therefore the fewer openings the better, and these should be on the sunny 
side. Fig. 1 (opposite) would form a useful arrangement with the cross walls run¬ 
ning north and south ; fig. 2 shows the inside walls east and west; fig. 3 develops 
the mutual-exchange-of-caloric theory to the utmost, and will probably prove the 
most successful in cold localities; fig. 4 (p. 46) shows a front elevation of fig. 3; and 
fig. 5 a rough perspective sketch of a glass garden. From this it will be seen that 
these gardens are not only useful, but highly ornamental. To the florist they 
will prove a new source of pleasure for the warming and shelter and training of 
many of his favourites, such as tea roses, &c., while to the pomologist they will 
