586. Envelope Opener.—Most people open envelopes at the end, often with trouble and awkwardly, but almost every envelope has one of the flaps a little loose near the corner. A small flat piece of steel with ivory handle such as could be disposed of for ten cents, would be salable.
587. Mail Stamper.—A stamper constructed upon a letter box so that it would be impossible to insert a letter without at the same time stamping it. The United States Government would pay a large sum for such a device.
588. Rotary Stamper.—A wheel broad enough to contain the name desired, and which is operated by taking the handle and drawing or pushing the wheel over the matter to be stamped. It would be ten times quicker than the ordinary way.
589. Invisible Ink.—An ink which is invisible, and must be treated by some chemical to make it appear. It would be invaluable to those carrying on a secret correspondence.
Section 15. Money in Dress.
590. Bachelor’s Buttons.—Invent an eyeless and threadless button, somewhat on the style of the envelope-clasp. The million or more bachelors would surely buy them.
591. Shoe Fastener.—Some device is needed for the quicker and surer way of fastening shoes. The button is inconvenient and the tie is unreliable. The Foster kid glove fastener made the inventor a man of millions.
592. A Trousers’ Guard.—One which will effectively prevent the wear at the bottom. Trousers commonly give way first at the end of the legs. The trousers-wearing world is vexed by garments frayed at the bottom.
593. Twentieth Century Shoe.—It will be one without laces or buttons. The upper can be taken off or put on instantly when desired, and yet be waterproof. There is a gold mine in that shoe.
594. Combination Tie and Collar.—A time saver which can be adjusted instantly, and yet be separable when desired. You would not have lost the train but for the delay in fixing your collar and tie. Thousands of minutes saved every day mean as many thousands of dollars in the pockets of the fortunate inventor.