This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In response to "Wm. H. B.'s" queries, I would say that the fires in a steam apparatus may be left oyer night. Steam may be carried up or down at pleasure if certain rules are followed - and the temperature of the steam pipes is not changed.
Providing the boiler be large enough a dwelling house may be heated from the same boiler as the greenhouses. I should not advise placing the boiler in the greenhouse. Do not imagine that a threshing machine boiler would be of sufficient capacity to do much heating.
The pressure of steam required is from one to five pounds. Regarded from an economical point of view, steam may be carried from 200 to 300 feet with but very little loss; if the pipe be well covered, and the pressure increased, it may be carried much further. I trust the above answers will enlighten "Wm. H. B".