X. THE BASS-BAR.
After the F-holes have been cut out, the bass-bar can be fixed. It is made of pine and should be prepared in such a way that the year-rings lie perpendicularly to the belly. The height of the bass-bar under the bridge is 10 m/m. and at the two ends 4 m/m. The bass-bar must be 6 m/m. thick in the middle, decreasing in thickness by 1 m/m. towards the ends. The length should be 280 m/m. The bass-bar must be glued on so that it lies 35 m/m. from the bottom edge and 40 m/m. from the upper one. In order to determine exactly the position of the beam, the width of the bridge should be precisely marked as 40 m/m. on the inside of the belly and the bass-bar should then be placed to coincide exactly with the G-foot of the bridge, giving it at the same time such a slanting position as to bring its upper end within 4 or 6 m/m. of the middle line of the belly, while its lower end should, on the contrary, be purposely placed farther away from it. (See illustration).
In order that the bass-bar may obtain the right tension, the side of it lying next the belly must be slightly curved, sufficiently so for both ends, before they are glued, to stand away about 2 m/m. In the process of glueing, the ends must be firmly pressed down. The height of the bass-bar under the bridge should be 8 m/m., while at the ends the measurement should amount to 4 m/m. It is scarcely necessary to remark that the proportions of the bass-bar vary in different violins, according as they are smaller or larger, high or flat, strong or weak. A few examples are given here. In a violin of the ordinary type, no matter whether it be large or small, the proportions will be found to coincide with the above statement, while a highly arched violin has a less slanting and less tightened beam than the latter. In the case of wood of a thickness less than 1¹⁄₂ m/m., the beam should be 1 to 2 m/m. more towards the interior, and also be placed from 3 to 5 m/m. more slanting, and must in that case also be from 1 to 2 m/m. thicker. A bass-bar under strong tension gives a sharp and clear tone, while one of less tension gives a fuller and softer one. With bass-bars of the height of 12 and even 15 m/m. (so-called acoustic bass-bars), it is not possible to achieve any success. The fixing of the bass-bar completes the interior construction of the violin, and consequently the glueing-on of the belly can now be proceeded with.
XI. THE HEAD OR NECK.
In Fig. 8 we have a very beautiful model, representing as it does a perfect specimen of Stradivarius. Its form can be obtained by exactly copying the external outline and the measurements I-XV. The inner curve of the head must be worked out as shewn in Fig. 8 b. The back at the head (Fig. 8 c) should be 4 m/m. thick on the upper side and gradually increase by 3 m/m. towards the under side, so that at this point it reaches a thickness of 7 m/m. The peg-holes must be placed exactly as shewn in the model. If they have short heads, they can be placed a few millimetres nearer together from A to G without destroying the appearance of the instrument. The wood for the head and neck must always be so chosen that the grain and surface lie horizontally.
XII. THE DIMENSIONS, LENGTH OF NECK AND BODY.
None of the old violin makers have attached more importance to the right position of the F-holes than Stradivarius; hence we gather that he fully recognised the importance of the dimensions of the body, and in his violins we always find that the same measurement is retained between the interior incision of the F-holes and the upper edge. We shall see later on the great advantages that would accrue to the musician, if all violin makers would observe the same rules in the adjustment of the dimensions. I repeatedly have cut off the necks of hundreds of violins, and by correcting the proportions have made the possessors of them entirely contented. How many a student has drudged on through life with a badly proportioned instrument, and in consequence has never succeeded in obtaining that certainty on his instrument after which he has diligently striven. We must now, however, enter rather more into particulars.
I hope that what is to follow, may enable everyone to judge and prove for himself, whether his violin has the correct dimensions or not. We will adhere to the measurement accepted by Stradivarius (see Fig. 1 a a a), which is exactly 195 m/m. from the upper edge to the incision of the F-hole, and call it the normal measurement. From this we learn that the length of the neck, that is to say, the distance from the lower edge of the nut (the point where the finger-board begins) to the upper edge of the belly (b b) should be exactly 130 m/m., and the whole length of the body should bear the same proportion to the length of the neck, as 195 m/m. bears to 130 m/m., or to put it still more plainly, if we take the total of the two lengths, namely 325 m/m., and divide it by five, the length of the body should be equal to three of these parts and that of the neck to two of them. Should a violin have a longer or shorter body measure than that given above, the neck must still be in proportion with it of two to three, that is to say, if the whole measure be divided into five parts, two of such parts will give the length of the neck. By these means, correct dimensions will be obtained, and a performer will easily accustom himself to the proportionate position of the neck, and forthwith obtain certainty of execution. If only the proportion of the neck to the body be correct, a performer will scarcely notice, whether the whole measure from the bridge to the upper nut is 5 to 10 m/m. longer or shorter. Great care must be taken in placing the upper end of the finger-board; it should be placed exactly at right angles with the under curve of the head (a), a point which is often paid very little attention to, and yet is one which is of the utmost importance. For instance, if the upper nut be placed too far beyond the angle (a), the hand must of necessity be stretched backwards in an uncomfortable position, or the fingers will fall too high upon the strings. On the other hand, if the nut be placed too low, the hand has no certain position upon the curve of the neck, and consequently will play flat in the first position and sharp in the third. It has often been said to me by musicians, and especially amateurs, that their violins played sharp in the first position and flat in the higher ones, and the contrary also has often come under my notice. The sole cause of these imperfections is the disproportionate relation in the length of the body and the neck, for whatever may be the distance between the bridge and the nut, whether long or short, the position of the different tones themselves is exactly determined by the laws of acoustics, and always remains in the same relation to the vibrating string.
I have given in Fig. 12 the exact position of the tones on the A-string, according to the normal measurement of 325 m/m. given above. The first tone played (B flat) is always exactly the eighteenth part of the whole length of the string from the nut to the bridge; the second tone is the eighteenth part from the first tone, and so on. If the finger-board is 268 m/m. long, the high E on the A-string will coincide with the lower end of the same. The above-mentioned imperfection is also caused by the neck being either too long or too short; in the first case a performer would play too sharp in the third position, and too flat in the second; in the higher positions also, he would have difficulty in finding the correct place for the fingers.