UNDER the auspices of Science Service, Dr. E. J. Prindle gave, on Nov. 13, a radio talk on the American patent law system. He pointed out how backward agriculture and manufacturing were prior to the introduction of the patent system, which gave the inventor the exclusive right for seventeen years to make, use, and sell his invention. So great is the transformation made by the introduction of machinery, that in garnering wheat crops one man can, by its use, do the work formerly requiring ten men. Only one man is now required for every 250 acres. The making of agricultural machinery is a very large industry. The expense of developing a single invention often runs into hundreds of pounds, and sometimes, as in the case of tho Curtis steam turbine, into hundreds of thousands of pounds. Without the possibility of recovering this sum and making a profit on the invention, neither individuals nor companies can afford to make and perfect inventions. Without the patent law, Edison could not have accomplished his great work which has benefited humanity. In connexion with electric lighting alone, Edison took out 375 patents. As a patent for an invention gives a monopoly, some think that it is therefore harmful, as many monopolies undoubtedly are. But a patent only gives an inventor a monopoly of that which he creates; it takes nothing from the public, and at the end of seventeen years the public receives the invention free. In normal times, the patent system has greatly increased the field of employment.