Guy walks into a bar with a slab of asphalt under arm.
Says to the bartender:
"I’ll take a beer, and one for the road."
Edison patentIn 1907, Thomas A. Edison was issued a patent for a "Diaphragm for Talking-Machines" (U.S. No. 855,562) that "will be readily responsive to vibrations of comparatively great amplitude." The invention comprised a duplex diaphragm made of at least two disks, each of which is radially sloted so that each disk constitutes a series of reeds. By staggering the slots of the disks, a continuous surface is presented for actuating the sound waves. The disks, made of mica about one-thousandth of an inch thick, are cemented together with an elastic cement, such as a solution of gum rubber. |
