From the program notes of Cursive, composed in 1962. [continued]
The two instruments move at different tempi with accelerando and rallentando as indicated. The signs or indicate where the two parts should coincide if the players strictly observe all tempo indications. The following is given as a guide for coordinating the tempi:
The signs indicate a continuous stepwise dynamic gradation of all the pitches included, from pp to ff in ascending or descending order. The following is given as a guide only in grading the intensity:
In measures so marked, all note values are only qualitative indications without exact proportional durations. ( = approx. 116)
From Measure 49 through Measure 71, wodden slabs, metal slabs, and metal chains of appropriate weight, thickness, and length should be placed across all strings from contra D sharp to three-line F natural, inclusive.
Commonly available materials such as bookshelf brackets (for the low register), rulers (for the cross-stringing section), triangular scales (for the middle register) and ball-chains (for the high register) may be used.
The materials should not be placed close to the dampers and care should be taken to insure that all strings are touched, overlapping the material if necessary.
The timbre should be uniform throughout. It should be metallic with an audible but not dominant buzzing. Except when trilling (Measures 60 and 65), the materials should have a minimum amount of rattling over the strings.