In a publication on Patents published about fifteen years ago, the following articles were asked for, which have since been invented, and which are making their inventors money:

(Note the organization of the "White Cross Milk Companies" in the cities of Philadelphia, Boston, New York, Baltimore and Washington, at this writing. Milk prepared by this process is said to keep for several months, and will be absolutely free from germs and bacilli. It is a new process.)

The above list will serve as an illustration of the fact that inventors are persistently supplying what the world needs in the way of new devices and machines.

SUPPLY AND DEMAND.

"Where there's a will there's a way."

Do not imagine that anyone is lying awake at night waiting for your invention to come out, because they are not. All of us consider ourselves pretty comfortable, and we are not bothering much about any new inventions. Another mistake inventors often make is that of endeavoring to make the public want their device. The proper thing to do is to invent something that the public already wants. In other words, "follow the lines of least resistance."

There are many good things which are very ingenious, and perfectly novel and patentable, but which are in lines in which there would not be enough sale in ten years to pay the inventor the expense of getting out patents. Yet plenty of such things are patented almost every week, in this country. "Some time there could be but one customer,—say, the government, or some great corporation,—and there may be reasons which are obvious, and others not so plain on the surface, why you could not even make them a present of your invention."

CHAPTER VI.
GROWTH OF THE FIELD OF INVENTION