THE OBJECTIVE OF THIS STUDY WAS TO COLLECT INFORMATION WHICH WOULD LEAD TO MORE EFFICIENT TEACHING OF SUCH FUNDAMENTALS OF BRASS INSTRUMENT PERFORMANCE AS PITCH, DYNAMICS, AND ARTICULATION. FIVE FRENCH HORN AND FIVE TRUMPET PLAYERS WERE PHOTOGRAPHED BY MEANS OF CINEFLUOROGRAPHY DURING THE PERFORMANCE OF CERTAIN MUSICAL EXERCISES. REPRESENTATIVE FRAMES OF THE DEVELOPED FILM WERE PROJECTED ON TRACING PAPER FROM WHICH MEASUREMENTS OF VARIOUS ORAL ADJUSTMENTS WERE TAKEN AND SUBSEQUENTLY SUBJECTED TO STATISTICAL ANALYSIS. THE GENERAL CONCLUSIONS WERE--(1) THE MOST COMMONLY USED TONGUE AND PHARYNX POSITIONS FOR BOTH INSTRUMENTS ARE SIMILAR TO THE POSITION INTERMEDIATE BETWEEN THAT USED TO FORM THE VOWEL "AH" AND THAT USED FOR THE VOWEL "OO." (2) SEVERAL SUPRALARYNGEAL ADJUSTMENTS ARE RELATED TO CHANGES IN REGISTER. (3) NOTES WITHIN SLURRED INTERVALIC SEQUENCES ARE USUALLY BEGUN WITH A SLIGHT UPWARD AND FORWARD JERK OF THE TONGUE. (4) VOLUME MAKES NO IMPORTANT DIFFERENCE IN SUPRALARYNGEAL POSITIONS. (5) THE TONGUE REMAINS SLIGHTLY HIGHER AND FARTHER FORWARD DURING TONGUED NOTES THAN DURING SLURRED NOTES. (THE MUSICAL PASSAGES USED FOR THE STUDY AND A SAMPLE TRACING OF TONGUE AND PHARYNX POSITIONS ARE INCLUDED.) (JS)