Take a piece of deal free from knots and shakes, and plane it smooth and true. Let it be of the shape of [Fig. 1], three-sixteenths of an inch thick, six and a half inches wide at the top, four and an eighth inches wide at the bottom, and twenty-three and a half inches along the side which is at right angles to the ends. The slope will be just a trifle longer.
This piece of wood is for the bottom of the box. Now for the sides. Make them out of quarter-inch stuff, twenty-three and a half inches long and one inch and five-eighths wide. For the ends take two pieces of three-eighths stuff an inch and five-eighths wide; and let one be six and a half inches and the other four inches long. For the tops, as shown in [Fig. 2], take two slips a quarter of an inch thick and two inches wide at one end, and an inch and a half wide at the other.
Let the wood be as perfect in quality and equal in thickness as possible, and glue up the box—without the tops—as evenly as you can. The box can be nailed or screwed if you think it will be easier for you, but the result will not be so satisfactory. The box is like a fiddle, and the more of a perfect shell it is the truer and fuller will be the sound.
FIG 3
FIG 4
In the centre of the box glue in the bridge, which will be about five and a quarter inches long and half an inch wide, and should stand clear of the bottom and clear of the tops. Then in the broad end, at two and a quarter inches from its sides, cut the slots, as shown in [Fig. 3]; and at the other end, as shown in [Fig. 4], cut the slots one inch and a quarter from each side. Below each slot is shown a small circle. This represents the head of the screw or tack round which the twine is strung on which the musical plates are to rest.
For the string use very fine twine, crochet cotton, or silk, and stretch it very tightly, and fasten it off at the end it started from; that is to say, fix it at the broad end under the tack, then pass it under the tack at the narrow end, then under the other tack at the narrow end, and then bring it up to the broad end and there finish it off. It should be very tight, and just rest on the bridge in the middle.
The next thing is the glass, which should be cut in inch strips, and fixed on to the strings with a drop of sealing-wax. Let us have eighteen notes ranging from B to E in the key of C. The true dimensions and position will have to be found by experiment, but for glass a sixteenth of an inch in thickness the following will be found the suitable lengths. B should measure five and three-eighths; C, five and a quarter; D, five; E, four and seven-eighths; F, four and five-eighths; G, four and a half; A, four and three-eighths; B, four and a quarter; C, four and an eighth; D, three and three-quarters; E, three and five-eighths; F, three and a half; G, three and three-eighths; A, three and a quarter; B, three and an eighth; C, three and an eighth; D, three and an eighth; E, two and three-quarters. These are the lengths for glasses an inch in width.