“I remember very well indeed the receiver with a steel wire, surrounded by silk-covered copper wire. The first one was placed on an empty cigar-box, arranged thus:—
Fig. 37.
“The wire was a knitting-needle and the copper wire was spooled on a paper case.
“The spiral was supported by a little block of wood, so as to allow the knitting-needle not to touch it anywhere. Later on a smaller cigar-box was invented as a cover—thus; ([Fig. 38])—having two holes cut into it like the f-holes in a violin.
