If the notes of the different positions are to be taken upon two strings, the finger goes with it to the higher position, but without necessarily remaining on the string.
In proceeding downward to another position, the finger on the last note slides with that which is proceeding in advance so far as to find its place in the lower position, but with the understanding that in case the note that follows is not to be played with the same finger, it must not remain down.
If the first note of higher position is to be played by a finger which is not the last used in the lower position, it must slide with it until the proper place in the higher position is reached, but must be lifted as soon as the finger which has to play the first note is put on the string.