I propose to describe a method of making an electrical machine of small dimensions, but capable of performing all the experiments that are likely to be required of it.
Fig 1.—Back of Rubber, Showing Position of Hole.
For the stand of the machine take a piece of wood (deal will do, but mahogany would be preferable) 14 inches in length, 8 inches in breadth, and ⅝ inch in thickness. To the bottom of this fasten two more pieces of the same wood, 1¼ inches broad, 8 inches long, and ⅝ inch in thickness at opposite ends, so that the edges are flush with the board. This forms our stand, on which we now proceed to erect the machine. Take another piece of the same wood, 7 inches long by 2½ broad, and ⅞ inch thick and fasten it firmly by four screws at the ends to the base board at a distance of half an inch from one end of its length and in the center of its breadth.
We now take two pieces of wood 14½ inches long by 2¼ inches broad and ½ inch thick, and fasten them upright to the opposite sides in the center of the piece just fixed to the board. They must be fixed very firmly to it with several screws, as they have to bear a severe strain while the machine is worked.
P Plate. R R R R Rubbers.
Fig. 2. Diagram Showing Position of Plate and Rubbers.
If the reader can dovetail the ends into the cross board they will be held much more firmly. At the top of these pieces another piece of wood, 3¼ inches square by ⅜ inch thick, is fastened by screws into the upright pieces, so as to hold all firmly together.
