I finally got my book ("The Last Trumpet: A Survey of the History and Literature of the English Slide Trumpet" by Art Brownlow) out and did a little reading.
Originally Posted by TopGun
The instruments were pitched in F, but usually had additional crooks to make it possible to play in other keys. A web search yielded this site about the slide trumpet, which describes it better than I have.
"The standard English slide trumpet was in F, with crooks to lower the pitch to E, Eb, D or C (or by combining crooks, to Db, B, Bb or A) and had sufficient length in the slide to lower the pitch of open notes by a semitone or, in some instances, by a whole tone."
With the fundamental changing based on the crooks used, any chart would obviously be based on the key of the fundamental. Most slide movement would be to correct out-of-tune partials (e.g. 11th, 13th) or to lower any partial a half or even whole step for musical effect. The lower the fundamental, the longer the instrument, and the more extension required to move a whole step. Depending on the instrument, whole tone shifts may not be possible in lower keys. The book notes that Thomas Harper Jr.'s "School for the Trumpet" publication of 1875 limited whole tone shifts to the key of D and higher.
I wish I had one of these instruments and could speak from direct experience rather than simply study of the text. The book is certainly a worthwhile purchase for anyone with an interest in the slide trumpet . It has many musical examples, descriptions of various designs, historical contexts, lists of players, etc.