Four things decide whether an instrument of this kind is any good, and none of them is what it looks like.
Timber
The dense hardwoods: bloodwood, which is red through and through and takes a glass polish; purpleheart, which is brown when cut and turns violet in the light; macassar ebony, black streaked with tan, dense enough to carry an engraved line without tearing; rosewood, zebrawood, bubinga, walnut, white oak. All of it is bought as boards and seasoned for a year in the shop before it is cut, because timber that moves after it is made into an instrument makes the instrument lie. Veneers are sawn, not sliced, where I can get them, which is thicker and truer in colour.
Dragon's blood
The red finish is not paint and not stain. It is the resin of the dragon tree, Dracaena and the rattan Daemonorops, which bleeds red from the bark and sets hard, ground to powder and dissolved in spirit. It has coloured violins, reliquaries and the gilder's bole for as long as any of those have existed. Built up in thin coats over a pale timber and rubbed back between them, it lets the grain show through the red like a lamp behind a curtain. It is the colour people ask for by name.
Brass
Lens rings are turned from thin-wall tube, thirty-two thousandths, so that the ring is a fine line rather than a bezel. Feet are turned from solid bar. Pencil clamps and the thumbscrews that hold them are made in-house, because the ones that can be bought are pot metal. The engraved plates are cut, not etched. Rods for dowsing are drawn, not cast, because cast brass is never straight.
Phi
Every board and every planchette is cut to one to 1.618, the golden rectangle, the width to the height. I did not start there. I started by measuring the antique boards and planchettes that sat well under the hand and finding, over and over, that they were close to it, and then I cut to it deliberately. The proportion is the same at both scales, so the pointer is the board in miniature, and the pivot of the board's arcs sits where the spiral converges, which is where the eye rests. That is the whole of my mysticism about it. The figure is below, and it can be drawn with a compass.
The case
Black-lacquered, hinged, lined in velvet, cut to the instrument. My instruments travel and are kept, and both deserve a box. The skeletal planchette's case is called the Ossuary; the others are not named, but they are made the same way.
