This acquiring of the cup-like position of the hand will be found enormously useful later on, in the playing of scales and arpeggios , as it allows easy passage of the thumb under the other fingers. In connection with the striking of the keys by the fingers, I would further say that merely putting down the finger and letting it strike with its own weight, is no good, as the sound produced thereby is inadequate and uncontrolled. My idea is that when lifted, the finger must be brought down with a certain amount of pressure upon the note which is struck.
This pressure should be produced from the forearm and transmitted through the fingers to the key, the wrist being all the time absolutely relaxed. Later on, as the student arrives at a higher development of finger technique, the articulation can be exercised purely from the fingers, but in the beginning, in order to acquire a full round tone, the control must be taught from the forearm by means of pressure from that part. Again, above all, I cannot too much insist upon the necessity for relaxation of the wrist,” and the rest of the body, for in it consists, I am convinced, half the secret for obtaining an easy and sure technique.
It must also never be forgotten that as the piano is a purely mechanical instrument, the great object must be to produce all gradations of tone without the sound being either forced, harsh or stiff. Moreover, the cardinal principle in the production of such tone is that the body, and especially the wrist, remain in complete relaxation. Nothing tends so much to hardness of tone on the piano as any rigidity in any part of the body. Also to obtain this most precious quality of flexibility, the articulation of the fingers must be entirely generated by the muscles of the hand, and controlled, as I have already explained as regards force, by the forearm.