William F. Semple, a dentist, was awarded the first US Patent on chewing gum in 1869. His recipe contained powdered chalk.
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| Number | Title | Issue Date |
| 7596236 | Loudspeaker with direct emission and optimised radiation The invention concerns a mobile membrane loudspeaker equipped with a partial closure optimising its radiation. The invention is characterised in that the loudspeaker with mobile diaphragm (19) attached to a rigid frame (15) defining an acoustic emissio... | 09/29/2009 |
| 7178629 | Electroacoustic public address unit with acoustic horn or waveguide A horn or waveguide public address unit, enabling to adapt the dispersion characteristics of the horn or waveguide. The unit is provided with at least one profiling component (21a, 21b) constituting a removable dispersion shaper, capable ... | 02/20/2007 |
| D500025 | Loud speaker | 12/21/2004 |