176 GREENHOUSE CONSTRUCTION AND HEATING. 
the water will flow almost as well one way as the other, 
but it is the right way, and should be followed whenever 
practicable (see Fig. 115). 
Before commencing to caulk the pipes up, take care 
that each spigot end is pushed quite ‘‘ home ” in its socket, 
otherwise the rope-yarn, or whatever kind of packing is 
employed, may become forced over the end, and interfere 
with the current. Caulking renders the pipes comparatively 
firm and steady, and when finished the whole ought to 
be gone over carefully with the spirit-level for the last 
time, before putting in the cement. 
When a length of piping of any size has to pass into one 
of a larger gauge, or vice-versa, what are termed reducing 
sockets are usually employed. In high-class work these 
are indispensable at certain points, but for rough jobs, 
or where the pipes are out of sight, as beneath beds 
and stages, we never trouble to use them, but just 
run the ends of the smaller pipe well into the larger 
(whether socket or spigot end is immaterial), packing 
it round well with rope-yarn—a firm collar may be made 
by binding tightly round the smaller pipe, near the end, 
with this—and then filling up with fresh cement, into 
which some small pieces of broken brick are pressed. In 
some cases a collar of wood or stout leather is used, but 
however managed, this makes a sound and safe joint, if 
properly done, even where a Qin. pipe is thrust into a 
4in. one. In fact, one can do almost anything in the way 
of jointing pipes, whether of iron or earthenware, with 
this invaluable material. I have made over fifty cement 
joints with it in quite a small but rather complicated 
apparatus, in which all sorts of odds and ends of piping 
