398 Professor G. H. Bryan [March 19, 



certainly to be found in the old mechanical pianotist in 1902, which 

 was played with thick cardl^oard or canvas rolls, and it may date from 

 still earlier. I consider this feature unnecessary, and its use un- 

 desiral)le on account of its very limited capabilities. 



The object of my experiments has been to apply dynamical and 

 physical principles lo the control of what I will call the striking- 

 action in piano-players, as it very soon appeared to me probable that 

 by so doing it would be possible to obtain differences of effect that 

 could not be produced by purely mechanical methods, and in particular 

 to acquire a certain amount of independent control over the different 

 parts of a chord the notes of which reached the tracker board simul 

 taneously. Naturally these experiments have been regarded by the 

 average " practical " expert with the same kind of scepticism and 

 opposition as my earlier attempts to advocate the necessity of apply- 

 ing tlie principles of rigid dynamics to the stability of aeroplanes. 

 For this reason it is necessary to discuss the problem in great detail 

 here. 



The ordinary practical man persists in asserting that in striking a 

 note or chord on the piano everything depends on what he often 

 inaccurately calls the " force of the blow," He says that you can 

 increase or decrease the force of the blow, but that the only effect 

 will be to play the whole chord louder or softer. He says that you 

 cannot bring the bass or treble parts into prominence unless you 

 connect the pneumatics with different degrees of vacuum, and it will 

 be found that many commercial music rolls have the chords cut in 

 very objectionable arpeggios in order to enable an air valve to be 

 opened or some equivalent increase of pressure effected between the 

 playing of one note of a chord and another. I have been told over 

 and over again that it is mathematically impossible to produce the 

 effects which I am continually producing on my player at Bangor, 

 and without which I regard no piano-player as worth playing. 



Now any mathematical physicist will understand that what these 

 engineers call " force of the blow " is in reality a very complex 

 phenomenon. In my piano I find that a fairly soft note is produced 

 in the middle of the scale when the hammer strikes the strings with a 

 velocity of 30 cm. per second, and that the hammers themselves rise 

 through a height of about 5 cm. This means that if the acceleration 

 ivere imiform the operation of depressing the key and releasing the 

 hammer would occupy one-third of a second. But during the opera- 

 tion the pressure applied to the key may be varied in an infinite 

 number of ways. It may be increased or decreased. It may be 

 made very large at the commencement of the blow, sinking to zero 

 at the end, as when a finger-pianist strikes the note from a height ; 

 or it may be very small at first and gradually increased, an action 

 which some describe as a " caressing " touch. But the check action, 

 which for a horizontal piano was first invented and patented ))y 

 Erard, and for which equivalent devices will be found in the vertical 



