ent, two of
sand and four of gravel or crushed stone with sufficient water to make a
mixture that will pour like thick mud, and put the iron pipe posts in
their permanent positions, seeing that the purlin is level and the posts
upright. (If necessary, the purlin can be weighted down until the
concrete sets.) Then put into place the ventilators, glazed, and the
headers for the same--short pieces of wood, cut to go in between the
sash-bars,--and fit these up snugly against the lower edge of the
ventilator sash.

When laying the glass in the roof, which will now be ready, use _plenty_
of putty, worked sufficiently soft for the glass to be thoroughly bedded
in it, and leaving no air-spaces or crevices for the rain to leak
through later. If this work is carefully done, it will not be necessary
to putty again on the outside of the glass, but it should be gone over
with white lead and linseed oil. Be sure to place the _convex_ surface
of every light up. The panes should be lapped from 1/6 to 1/4 of an
inch, and held securely in place with greenhouse glazing points, the
double-pointed _bent_ ones being generally used. The lights for the ends
of the house may be "butted," that is, placed edge to edge, if you
happen to strike good edges, but as a general thing, it will be more
satisfactory to lap them a little. The woodwork, before being put
together, should all receive a good priming coat of linseed oil in which
a little ochre has been mixed, and a second coat after erection. I have
suggested putting the glass in roof and sides before touching the
benches, because this work can then be done under shelter in case bad
weather is encountered. The benches can be arranged in any way that will
be convenient, but should be about waist-high, and not over four or four
and a half feet across, to insure easy handling of plants, watering,
etc. Rough boards will do for their construction, and they should not be
made so tight as to prevent the ready drainage of water. The doors may
be bought, or made of boards covered with tar paper and shingles or
roofing paper.

The house suggested above is used only by way of illustration. It may
be either too large or too small for the purposes of some of the readers
of this book, and I shall therefore give very briefly descriptions of
several other types of small houses, some of which may be put up even
more cheaply than the above. The plainest is the sash lean-to somewhat
like Fig. 3, which is made by