Steam Heating and Ventilation.
Chapter I.―Introductory.
The first really practical treatise on heating and ventilation seems to have been published in 1824 by Thomas Tredgold, and in that volume much space is given to the importance of securing adequate ventilation, and also to the merits of heating by systems of steam pipes. Mr. Tredgold gives accounts of several buildings which were successfully heated in this way. It is cited that the first factory in which steam was used for heating was a cotton mill belonging to a Mr. Neil Snodgrass, in which a steam heating system was installed in 1799. This was doubtless about the first instance of the employment of steam primarily and systematically for the purpose of heating. Mr. Tredgold describes a factory which was equipped with a steam-heating system in 1817 as a substitute for stoves, which had been previously used. The building was 90 feet by 30 feet, exposed on all sides, and four floors high. Each floor was warmed by a single pipe running the length of the building at the ceiling and midway between the sides. The system carried 30 pounds steam pressure, but besides embodying the most inefficient location for the radiating surface, the system, as described, did not have over 450 square feet of heating surface for a building containing 91,800 cubic feet of space. Mr. Tredgold states that the system showed great improvement, both in economy and results, over the previous method, adding that the employees suffered much less from "chaps and chills," so that one can only imagine the wretched condition of factory employees in cold weather previous to that time, even in the comparatively mild climate of England.
The problem of artificial ventilation antedates that of steam heating by more than half a century, though, of course, it does not antedate the heating of buildings by various methods more primitive. Mr. W. F. Butler, in a handbook on ventilation, pub-
