The strings.
Violin strings are made from the intestines of sheep. The lowest string has fine wire spun round it, silver wire being the best. Copper wire is greatly used, it being much cheaper. The best strings are obtained from Italy, from Rome, Padua, and Naples, although very good strings are also manufactured in Germany, at Markneukirchen. The value of a string consists principally in its perfect equality of thickness throughout; above all, there must not be knots in it. A string spun quite evenly yields accurate vibrations, and is on this account pure in tone.
In order to test the purity of tone of each string, it may be held as shown at both ends, pulling it rather tight, and then setting it into vibration with one of the fingers. If it appears double, thus:—
it possesses a pure tone; if, however, it appears threefold,—if only at one part of it,—it will be false.
Strings pure in fifths.
To obtain absolutely pure intonation, the strings must be pure in fifths, i. e., the notes in those higher positions which are pressed by one finger across two strings, must sound perfectly true. Many strings are rather thicker at one end than at the other; if this is not also the case with the adjacent string, or if the thicker end of it be not stretched in the same direction as the other string, then the two are not true in fifths with each other. Both strings must therefore lie from one end to the other regular in thickness, or else their thin ends must be laid in one direction.[6] In the latter case, however, all the harmonic notes are not true, and one also notices that the intervals in double-stopping generally, as well as in fifths, are not regular upon all the strings. A treatment is in vogue by makers of strings and instruments by means of which the strings are rendered quite pure in fifths. These prepared strings are, however, not so durable, nor so good in tone, as the unprepared. But it is of service to have always a few of these in readiness, as the violinist has not always time enough to select those strings which are true. Weichhold, Dresden, supplies strings pure in fifths, which may be recommended.
The string guage.
In order always to have strings of the same thickness, a string guage is used, which may be procured at any instrument maker.[7]