The material to be dried was stacked upon the slatted floor in loose piles, through which the heated air from below could circulate more or less freely. For years these dry-houses—they were not then dignified by the name of kilns—were only used in connection with certain manufactories for drying stock already cut up for tubs, pails, and other wooden ware; small boxes, chairs, and other furniture material; turned work and Yankee-notion stock in general; no regular lumber stock being subjected to the process.
Occasionally a little lumber for interior finish, where an extra fine job was desired, was run through the dry-house for a final drying, and later, after machine-made sash, doors, and blinds began to take the place of the old hand-made goods, being generally made from air-dried stock, they were sometimes put through the dry-house before being wedged and pinned.
These dry-houses contained such an element of fire risk that they were generally built in isolated positions as close to water as possible. Even then they were a constant menace to all surrounding property as well as to their own contents. Lumber, except in small pieces, dried in them was apt to be checked and warped or twisted more or less, and was not at all satisfactory save in the one feature of being free from moisture.
The fire risk at last became so great where the establishments requiring the dry-houses were situated in towns, and the restrictions of underwriters so onerous, that along in the fifties some crude attempts were made to substitute steam for the furnaces by conducting the exhaust from the engines running the works into the cellars.
It is not definitely known when or by whom the first attempts were made, but it is a fact that as early as 1855 the trial was made by a manufacturer in northern Massachusetts. But the experiment did not prove very satisfactory, for the reason that the steam had to be carried quite a long distance; the science of protecting steam pipes so as to prevent condensation was not as well understood as at the present day; the engine was none too large and the boiler capacity limited, and there was more or less back pressure.
But so certain were the experimenters that they were on the right road that they kept up the trials, though, from causes stated, making but little attempt to use the steam during the winter months. Success seemed near, when the panic of 1857 came on, and the house met with reverses that stopped all further experiments. Some additional attempts were made in the New England States during the next four years, but in a rather desultory way, when, the war of the rebellion coming on, the inventive genius of the country seems to have been turned in