My clarinet colleague in the Columbus Symphony, Woody Jones, came across this very old copy of Clarinet Magazine published in 1954. He gave it to me because it contains an article by my old teacher, Sidney Forrest.
It also contains articles by Anthony Gigliotti, Daniel Bonade, among others you can see on the cover of the magazine in the photo above. (click on the photo to see it enlarged)
Gigliotti gives advice to move fingers in a smooth manner and flex the air to attain good legato. He also writes a section on proper breathing which I will quote here, since it parallels much of my own advice on the subject.
[...] Mother Nature teaches us to breath correctly when we are babies, and we continue to perform this important function properly through early childhood. However, when a child reaches school age, he is inclined - perhaps because of the fact that he spends so much time in a sitting position- to allow bad posture to interfere with his correct breathing habits. Parents and teachers, noticing this begin to instill in him the false idea that he must stand up straight and expand the chest in order to breathe deeply, which actually causes a body tension that results in just the opposite to what is desired. In holding the mid-section rigid (as one must do, to expand only the chest), one prevents the correct functioning of the midsection, the only section of the body that is capable of normal expansion which allows the lowers lungs to fill properly. If you watch a sleeping person, you will notice that the expansion and contraction in breathing is in the region of the lower ribs, where the diaphragm is located. [...]
Bonade suggests adding right hand fingers to tune throat tones, and to relax the embouchure a bit to lower high tone.
Among other things, including some fun ads for bizarre reeds, there's an article on playing the mouthpiece upside down, with the reed facing up. Apparently several prominent clarinetists played the clarinet in this manner quite successfully, including Luigi Bassi, and the principal clarinetist of the Boston Symphony at the time, Gino Cioffi. According to the article, Mr. Cioffi switched to the traditional way of playing the mouthpiece, with the reed facing down, not because it was better, but because he was afraid of not being hired simply because he played in an unknown and unaccepted way. I had heard that the clarinet was played this way, but never knew to such high professional degree.
Sidney Forrest, who studied with Simeon Bellison, offers practical advice on playing high tones. I would like to quote his short article here.
1- Whether it be a high tone or a series of high tones, one must first hear the desired pitch mentally before trying to play it. Merely using the correct fingering will not produce the intended tone or tones.
2- Imagine that you are singing the desired pitch into the instrument - the clarinet at all times should be thought of as an "extension" of your voice.
3- take in the optimum amount of mouthpiece - the amount that will be suit you for playing in all registers. It should not be necessary to take in more mouthpiece at any time to reach a high note.
4- Stretch the corners of the mouth further back for high notes, as in saying "EE" or as in smiling. Be sure this is done only in moderation, in order not to disturb the "center" of the embouchure around the mouthpiece and under the reed. It should be emphasized that the basic shape of the lips - the fundamental embouchure - definitely remains constant.
5- When playing a large ascending interval, tilt the clarinet ever so slightly upward simultaneously with the change of fingering; e.g., solos in Egmont Overture, introduction; Night on Bald Mountain, Pines of Rome.
6- Give special support to high notes by raising the diaphragm (located between the abdominal and chest cavities) and pulling in the abdomen.
7- It is a good practice to flex the upper part and sides of the reed away from the mouthpiece. Insert and old but un-chipped reed or celluloid card between the reed and mouthpiece and bend the reed away from the mouthpiece firmly but gently and with a bit of spring in the motion.
8- A parting "don't." Don't bite, don't press, and don't squeeze the reed and/pr mouthpiece to play any high note.
This last note is typical of Mr. Forrest who often used humor or word games to help an idea stick.
Sidney Forrest, who is 92, is still alive and kicking. I visit him when I an in the DC area where I grew up. He still has useful and clever advice on playing clarinet.