80 GREENHOUSE CONSTRUCTION AND HEATING. 
on, but as the pure colour does not look well, and very soon 
becomes soiled, it is usually toned down with a little umber, 
grey lead colour, or blue—just enough to “take the raw 
edge off.” 
When putting on the last coat, or coats, a little care and 
taste in the choice of tints is by no means thrown away, 
certainly where an ornamental appearance is aimed at. A 
very good plan is to use a nice soft white—a French, or 
paper white—for the bulk of the woodwork (inside), and 
‘pick out”’ the tie-rods, standards and other ironwork with 
dark or light blue, or a pale sea-green looks very well and 
affords a little variety. 
The best time for all outside painting is in the early 
autumn, when, drying more slowly and sinking in better, 
it sets harder and lasts longer than if put on eavrlier. 
Painting done in the spring or summer dries quickly under 
the hot sunshine, and even if it does not crack or peel off, 
perishes much more quickly than that done in the autumn. 
Never use tar, or the so-called ‘‘ black varnish,” which 
consists of the same thing to a great extent, inside a plant 
house of any kind, for any purpose. Both give off a 
horrible smell, when the place gets warm, for some time, 
and the fumes have a most destructive effect upon plants 
of all kinds. Beyond this, wherever oil paint touches a 
bit of tar it turns to a dirty brown or drab hue. A little 
tar is only admissible in the case of wooden gutters, etc., 
outside the house. 
Iron.—Iron is now employed to a considerable extent in the 
construction of greenhouses, though by many it is objected 
to on account of its greater conductive power rendering 
the loss of heat considerable as compared with wood. 
