XVII. THE BRIDGE (Fig. 10).
The bridge is made of maple and should be 40 m/m. wide and 35 m/m. high, at the bottom it should be 4 m/m. thick, on the top 1¹⁄₂ m/m. The width of the feet is not to exceed 9¹⁄₂ m/m. (Fig. 10 a).
The feet must be fitted exactly to the belly and towards the back should be sloped sufficiently, so that on the lower side of the bridge they form an exact right-angle with the centre line of the belly.
It is advisable to powder the feet a little with chalk to prevent the bridge from being so easily displaced as would otherwise be the case.
The feet of the bridge should stand exactly on the line of connection between the notches of the F-holes (Fig. 7 a a) and at an equal distance from them on either side. The notches on the bridge for the E and G-strings are to be 34 m/m. apart.
The lower end of the E-string should not be more than 4 m/m. from the finger-board at the very most, that of the G-string about 6 m/m., but never more. The height of the strings is, however, very often adjusted to the wish of the performer. Herr Joachim, the great violinist, always adopts the above measurements on his violins.
A highly arched violin does not require so high a bridge as a flatter one, whilst an instrument with a thin belly needs a thicker bridge than one of stronger make. These proportions must be carried out very precisely, as well as the measurements with regard to the hardness or softness of the wood and the strength or weakness of the bridge.
If the bridge be thick below and thin above, the tone will be clearer than it would be if these conditions were reversed. If the heart in the bridge be cut rather small and high up, the tone is rendered harder, a large heart cut in the surface of the bridge will make the tone fuller. The use of hard wood for the belly necessitates soft wood for the bridge, and loosely grained and soft wood needs a hard wood for the latter.