| 摘要 |
<p>The protective cover for a bed mattress consists of a sheet of hemp around which is a copper coil. The hemp sheet is lined on both sides with a sheet of cotton or other material, and the whole cover stitched together. Alternatively the mattress cover can be made of a fabric incorporated metal threads, especially made of copper, which on one side has an earth connection preferably of copper wire, and on the other side has a vertically pointing aerial. The aerial is formed by a metal, preferably copper, coil. The mattress cover has a waterproof envelope, preferably of plastics.</p> |
