"I had supposed it was because masons do not understand the philosophy of chimney-building," remarked Coleman.
"That is it exactly. The subject is not understood at all, because it has not been examined. Men build chimneys as they do, not because they know it is the best way, but because they do not know any thing about it. For instance, nearly every one thinks that smoke is lighter than air, when the reverse is true."
"I always had that idea," remarked Potts; "not because I knew that it was, but somehow I got that impression. But let us have your paper, and then we will discuss it."
Franklin read his paper, which was more elaborate and exhaustive than any thing of the kind ever published at that time. It named several definite causes of smoky chimneys, and furnished a remedy for each. What is still more remarkable, it suggested a plan of a fire-place or stove, that might remedy the smoking evil of some chimneys, and save much fuel in all. Subsequently, he invented what is known as the Franklin stove, or fire-place, though it was sometimes called the "Pennsylvania stove." It was regarded as a very useful invention, and, for many years, was in general use.
"Apply for a patent on your stove," suggested Coleman; "there is much money in it; and you ought to have it if any one."
"Not I," responded Franklin. "I am not a believer in patents. If the invention is a real public benefit, the people should have the advantage of it."
"Nonsense," retorted Coleman; "no one but you harbors such an idea. I do not see why a man should not receive pay for his invention as much as another does for a day's work."
"And there is no reason why the inventor should not give the public the benefit of it, if he chooses," answered Franklin. "Governor Thomas offered to give me a patent on it, but I told him this: As we enjoy great advantages from the invention of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously."
"And nobody will ever thank you for it," added Coleman.
"I don't ask them to thank me for it; I give it to them without asking one thank-you for it," replied Franklin, who was in a very happy mood.