The H.L.Clarke Tech Studies appear to have been first published in 1912.
Here are some quotes which have influenced my thinking:
1. "It will be found possible to play the highest, as well as the lowest note...with equal tone quality".
2. "One cannot expect to attain the highest point of excellence without hard work and perseverence".
3. "Never be satisfied with yourself".
4. "Most players practice incorrectly and by NEGLECTING THE ELEMENTARY WORK, lose many of the benefits to be gained".
5. "Always remember that only a slight pressure and not brute force is necessary to produce a tone".
6. And perhaps the greatest revelation,
for myself, is the statement:
"Practice each exercise eight to sixteen times in one breath. ......KEEP THE LIPS MOVING! CONTRACT THE LIPS SLIGHTLY IN ASCENDING, RELAX IN DESCENDING! (The caps and punctuation, for emphasis, are mine.)
And so, a complete prescription for beautiful, fluid, wide range playing, with greater endurance, is to be found in the first two pages of the H.L.Clarke Tech Studies!!!
It is however, terribly sucinct - so much so that it had no real effect upon myself until the fourth decade of my existence!
A very important quote from H.L.Clarke - Characteristics Studies Book:
"As a matter of argument, when the muscles of the lips are contracted for high tones, one would necessarily pronounce "Te", and when relaxed for the low tones, "Tu": consequently it would be unnatural, andalmost impossible to use the same syllable for tones in all registers on the cornet". H.L. Clarke
This is the rationale and basis for my "silent whistle", as I assume that most people can develop a "feel" which is, at least, related to the one which is necessary for playing a brass instrument.
Keep 'Em Flyin'!
PS - You may enjoy, or even find enlightening, my recording:
Hunt Plays the Clarke Tech Studies. The Etudes are played "as written" and "Up an octave". REALAUDIO clips found at: