Chapter 22

MATERIALS--BRAZIL WOOD--HORSEHAIR--THE ACTION OF ROSIN.

It is curious to pass in review the strange events--the causes, heterogeneous and improbable, that have produced many of the most important results in the history of man. What fiddler, for instance, when indulging in the customary smoke after an evening's "grind," realises his indebtedness for half his enjoyment to an unscrupulous Genoese pirate of the fifteenth century? Yet, seeing that in addition to wooden nutmegs, banjoes and other blessings of civilization emanating from the New World, America gives us both tobacco and Brazil wood (the only material of which it is possible to make a thoroughly good bow), I think that, if I may liken the violinist's mind to a temple of many shrines erected to all those who have contributed to his welfare and enjoyment, there should be one niche reserved for Christopher Columbus of egg-balancing fame.

It is also of interest to note how, as soon as violinists were ready for a perfect bow, Francois Tourte appeared on the scene and provided the much desired article. How he experimentalized on common sugar-barrel wood I have already set down in its proper place. This was, of course, to gain proficiency in the use of his new tools. In his search after a wood that should contain the essential qualities of strength, lightness and spring, he made bows of many kinds of wood, but was not satisfied until he tried the red wood imported for dyeing purposes from Pernambuco. I am afraid there are few who reflect on the significance of the fact that the exact wood required _did_ actually exist. Formerly the bow-maker had to buy the wood in the rough state just as shipped over, and then would begin the weary work of selecting those pieces suitable for his purpose. As a matter of fact they are few and far between, for this wood is particularly full of twists, knots and splits. Now this is done for him by firms who buy the raw material, select that with the desired straight grain and cut it into square rods ready for the craftsmen to work up into bows. A few years ago bow makers demanded very dense wood under the impression that it would be advantageous to have them as slender as possible, for the denser the wood the thinner must be the stick to preserve a normal weight. The fallacy of this method, however, soon made itself apparent, for, though you may thin down a stick _ad libitum_, the head _must_ be a certain height and breadth, consequently these bows were all more or less top heavy. A much lighter variety of wood therefore is now being used, and I must say the appearance of some recent bows by our best English makers is extremely fine; there is a greater sense of proportion apparent to the eye as well as to the hand.

Some of the cheap German and French trade bows are made of what the dealers call Brazilette wood, a wood somewhat allied to the true Brazil wood, but totally lacking in spring or firmness. I wonder whether violinists often realise when they take up a bow how many remote parts of the earth have contributed to this little magic wand! Wood from the West, ivory from the East, mother-of-pearl from the sea, gold or silver from Eastern, Western, or, it may be, Antipodean mines; and, when we add thereto the hair from the horse's tail, we levy a tax upon the three kingdoms, vegetable, animal and mineral, to minister to our enjoyment.

As much discrimination has to be exercised in selecting the hair as in the case with the wood, for it is essential that every hair in the bow be absolutely cylindrical and of equal thickness throughout. These have to be sought for very carefully and are not so plentiful as one would suppose, for the shape of a hair is regulated by that of the pore from which it grows and these are seldom circular, many being flat on one side, some, even, square or triangular. It has been estimated that the proportion of suitable hairs is not more than ten per cent. Tourte, according to Fetis, always preferred French hair for his bows as he found it "larger and stronger than that of other countries." I believe at present a quantity of Russian hair is used.

Tourte's daughter was of great assistance to him in selecting and preparing the hair. His method was to thoroughly cleanse the hair with ordinary soap, then to soak it in bran water and then, after removing all foreign matter, to dip in "blue water." A few years ago some misguided people tried bleaching the hair chemically. This, however, made it quite dry and brittle, and it has happily been abandoned.

The average number of hairs in a bow now-a-days is from 150 to 200. In Tourte's day a similar number were used.

A few words on the structure and action of bow hair and the real part played by rosin may not be amiss. As Mr. Heron-Allen truly observes "it is astonishing how few violinists know anything about the mechanical and scientific action of powdered rosin on tone production." And for the laity he says again that many think, when they see a bow being rosined, that it is being "greased to make it go faster."

If we examine a hair microscopically we discover a surface covered with minute scales. Ordinarily these scales lie close to the main shaft, but when rosin is rubbed along the hair small particles get fixed under the scales causing them to stand up somewhat like the teeth of a saw. These erected scales act on the string like so many infinitesimal _plectra_ and thus produce in perfection the sustained sound attempted in a grosser manner by the tremolo of the mandoline. It is simply a rapid series of shocks. A moment's consideration will suffice to realize that continuous pressure on a string would act as a deterrent rather than a promoter of vibration. In fact an unrosined bow gives continuous pressure and therefore produces no sound.

The hair is usually inserted in a bow in the natural position of its growth, _i.e._, the root end at the top, thus, as the scales point downwards, giving the greatest attack to the down bow. Some have tried placing half one way and half the other but I do not think a very perceptible difference results from this proceeding.