The first is in D, in playing which you should accelerate the motion a little each time, till you arrive at the quickest degree of swiftness possible; but two precautions are necessary in this exercise--the first is, that you play the notes _staccato_, that is, separate and detached, with a little space between every two, for though they are written thus-- [Illustration] they should be played as if there was a rest after every note, in this manner-- [Illustration] The second precaution is, that you first play with the point of the bow; and when that becomes easy to you, that you use that part of it which is between that part and the middle; and when you are likewise mistress of this part of the bow, that you practise in the same manner with the middle of the bow; and, above all, you must remember in these studies to begin the _Allegros_ or flights sometimes with an up-bow; and sometimes with a down-bow, carefully avoiding the habit of constantly practising one way. In order to acquire a greater facility of executing swift passages in a light and neat manner, it will be of great use to you if you accustom yourself to skip over a string between two quick notes in divisions, like these-- [Illustration] Of such divisions you may play extempore as many as possible, and in every key, which will be both useful and necessary. "'With regard to the finger-board, or carriage of the left hand, I have one thing strongly to recommend to you, which will suffice for all; and that is, the taking a Violin part, either the first or second of a concerto, sonata, or song--anything will serve the purpose--and playing it upon the half-shift, that is, with the first finger upon G on the first string, and constantly keeping upon this shift, playing the whole piece without moving the hand from this situation, unless A on the fourth string be wanted, or D upon the first; but in that case, you should afterwards return again to the half-shift, without ever moving the hand down to the natural position. This practice should be continued till you can execute with facility upon the half-shift any Violin part not intended as a solo, at sight. After this, advance the hand on the finger-board to the whole-shift, with the first finger upon A on the first string, and accustom yourself to this position till you can execute everything upon the whole-shift with as much ease as when the hand is in its natural situation; and when certain of this, advance to the double-shift, with the first finger upon B, on the first string; and when sure of that likewise, pass to the fourth position of the hand, making C with the first finger upon the first string; and indeed this is a scale in which, when you are firm, you may be said to be mistress of the finger-board. This study is so necessary, that I most earnestly recommend it to your attention.