People are not generally aware of the danger of fire connected with the exposure of wood for long periods to a comparatively moderate temperature. Mr. Braid-wood, superintendent of the London fire-engine establishment, stated before a committee of the House of Lords, that, by exposure to heat not much exceeding that of boiling water, timber is brought into such a condition that something like spontaneous combustion takes place; and that it may take eight years for the heat from pipes charged with or used to convey steam, hot water, or heated air, laid among the joists of a floor, or in the heart of a partition, or elsewhere in a building, incased in timber, to induce the condition necessary to the actual ignition of the timber".

The above is from the February Swiss Cross, but the Gardeners' Monthly has for many years past urged the fact on the attention of greenhouse builders. It may be added that enclosed wood fires quicker than when the wood is on some sides surrounded by the outer atmosphere.