The protection of an invention implies the dual problem of how to prevent others from stealing the product of one's mental labor, and of how to insure a fair share of its value to the inventor.

To solve that problem absolutely is of course no more possible than the absolute prevention of the pilfering of anything else of value in the world, but it may be made as secure as the present circumstances in the case will permit if the inventor, to use a slang expression, will be "on to the game." To be that, he first has to know with whom he has to reckon, and how the stealing is done, and the best way to checkmate it.