It is extraordinary the number and variety of rosins in the market; some in most wonderfully contrived boxes designed to keep the rosin dust from making the fingers sticky, or--more probably--to _sell_! Of all the different patents in this way, I find the ordinary book-shape by far the most satisfactory. The first quality of rosin is prepared by boiling down Venice turpentine. In a certain authority on violin matters I read that many soloists of celebrity use common kitchen rosin, but I cannot say I have much faith in the source from whence he can have received such information. It is advisable never to change the rosin used until the bow is re-haired, as in each there is some slight difference in composition that may not harmonize with what is already on the bow. CHAPTER XIII. THE PERFECTION OF THE MODERN BOW--DR. NICHOLSON'S PATENT BOW--VUILLAUME'S INVENTIONS--SELF-HAIRING BOWS--A FOLDING BOW--THE "KETTERIDGE BOW." It is worthy of note, as a testimony to the simplicity and perfection of the bow, that there have been so few attempts, since Tourte's day, to alter or "improve" it in any particular. The few experiments that have been made in this direction have in nearly every case proved failures and have sunk into speedy oblivion. One of the most remarkable productions in this way was the ponderous monstrosity invented by one Dr. Nicholson (Fig. 43). This hideous and unwieldy weapon was put forth by its inventor as the only correct form for a violin bow! It had to be haired with precisely 150 horse hairs dyed red. The reasons for this and the eccentric curve of the stick are subtleties into which I dare not venture! [Illustration: FIG. 43.] Vuillaume's erratic genius was responsible for sundry attempts at improving the bow, the most complex being the fixed nut. He was struck by the fact that with the ordinary nut advancing and retreating by the action of the screw it was possible for it to be not always mathematically in the same place. Also that as the hair gradually stretched by use, the length thereof increased as the same tension was obtained each time it was screwed up for use. This, of course, made a minute difference in the balance of the bow. He apparently considered this a serious defect and set about inventing a nut that should render the balance and the length of the hair immutable. This was his patent "_hausse fixe_." As the name implies the nut was a fixture externally but contained a smaller metal nut that travelled inside it. These nuts were very unsightly as they were much more bulky than the ordinary nut. It is curious that it never occurred to him that the movement of the internal nut would similarly affect the balance. A sort of windlass in the nut would have been more exact, but, as a matter of fact the difference is more theoretical than practical, and is imperceptible to the player, so the fixed nut, like many other examples of wasted ingenuity, died a natural death.