How to give orders in Angass

I'm researching Chadic imperatives at the moment, so I opened Angass Manual - written by H. D. Foulkes, Captain (late R. F. A.), Political Officer, Nigeria in 1915) to the appropriate section, and found it to consist solely of the following advice:

The Imperative is of the same form as the rest of the verbal forms, only uttered with the necessary tone of authority.

I suppose it's too much to expect an Edwardian captain to be able to transcribe tones, but I couldn't read that without bursting out laughing.

The book gets even better, with such cringeworthy gems as this "explanation" for phonological processes:

"The Angass, like most negroes, have a nice ear, and they endeavour to prevent harsh sounds coming together."

I particularly like how he explains that Angass grammar is really simple:

"The language is so simple in construction that I am hoping a study of it may help in elucidating the groundwork of more elaborated Negro languages."

since anything he can't get to grips with must not be part of its grammar:

"The only difficulty - but it is a very real one - in the colloquial is the apparently capricious employment of a large number of particles, the use of which, though immaterial from a grammatical point of view, is, however, necessary in practice, for without them the sentence certainly loses its flavour, and seemingly some of its sense, in that an ordinary man cannot understand a phrase unless it is enunciated exactly in the way he is accustomed to hearing it, and the omission or transposition of a word bothers him considerably."