jS. A. Hageman — A Just Intonation Piano. 227 



passes through an opening in the agraffe and between the wrest 

 pins, and connects with the horizontal arm of lever (not shown) 

 at the top of the wrest plank. 



FIG.2. 



The movable bridge b has a concave bearing conforming to the 

 convex surface of the slide, or way, c, so that the bridge may 

 adjust itself to the plane of the strings constituting a unison and 

 insure equal pressure of all the strings of the unison. 



The slide c, upon which tbe'bridge moves, has its upper surface 

 parallel to the dotted line a', thus equalizing the pressure of the 

 string upon the bridge at all points and avoiding undue and 

 unequal strain which would tend to put the piano out of tune. 



At the top of the wrest plank is a series of lever arms actuating 

 the bridges. By making these arms proportional to the strings 

 to which they correspond, compensation is made for the varying 

 lengths of the strings so that a given amount of motion (in arc) 

 produces uniform change of pitch in all the strings. 



These arms are attached to cylindrical rods which pass back to 

 the rear of the piano where the other arm of each is attached at 

 a right angle. The two arms and the connecting rod constitute a 

 lever of which the. cylindrical rod is the axis of motion. 



The lever arms at the back are furnished with octave con- 

 nections and on those pins are so placed that they are caught 

 when a pedal is pressed and brought into that precise position 

 that is required for the particular key that the pedal represents. 



The entire just intonation mechanism including the eighty- 

 eight bridges is made up of only two hundred and fifty mova- 

 able parts, is not expensive nor difficult of construction, nor in 

 any manner readily susceptible of derangement, but is durable 

 and reliable to the last degree. 



