In Ben Franklin’s time in the American Colonies there was not much of a demand for stoves outside of the largest cities, where wood was getting a little scarce and high, but the philosopher not only deemed it proper to invent an improvement in chimneys to prevent their smoking and to better heat the room, but also devised an improved form of stove, and both inventions have been in constant use unto this day. Franklin invented and introduced his celebrated stove, which he called the Pennsylvania Fire Place, in 1745, having all the advantages of a cheerful open fireplace, and a heat producer; and which consisted of an iron stove with an open front set well into the room, in which front part the fire was kindled, and the products of combustion conducted up a flue, and thence under a false back and up the chimney. Open heat spaces were left between the two flues. Air inlets and dampers were provided. In his description of this stove at that time Franklin also referred to the iron box stoves used by the Dutch, the iron plates extending from the hearths and sides, etc., chimneys making a double fireplace used by the French, and the German stove of iron plates, and so made that the fuel had to be put into it from another room or from the outside of the house. He dwells upon the pleasure of an open fire, and the destruction of this pleasure by the use of the closed stoves. He also describes the discomforts of the fireplace in cold weather--of the “cold draught nipping one’s back and heels”--“scorched before and frozen behind”--the sharp draughts of cold from crevices from which many catch cold and from “whence proceed coughs, catarrhs, toothaches, fevers, pleurisies and many other diseases.” Added to the pleasure of seeing the crackling flames, feeling the genial warmth, and the diffusion of a spirit of sociability and hospitality, is the fact of increased purity of the air by reason of the fireplace as a first-class ventilator. Hence it will never be discarded by those who can afford its use; but it alone is inadequate for heating and cooking purposes. It is modernly used as a luxury by those who are able to combine with it other means for heating. The great question for solution in this art at all times has been how to produce through dwelling houses and larger buildings in cold and damp weather a uniform distribution and circulation of pure heated air. The solution of this question has of course been greatly helped in modern times by a better knowledge of the nature of air and other gases, and the laws which govern their motions and combinations at different temperatures.