The generator was an RAF store, used used to indicate in the camera obscura, the position of an aircraft during high level bombing practice.
It could also be used for signalling.
Sometime early in WW2 the Mk1 ceased production, but was still in use, even when the Mk2 version had been produced.
They are described as being coloured smokes, probably to differentiate between aircraft bombing accuracy.
I have nothing on the Mk1, only that the container dimensions are identical to the Mk2.
Both marks were packed in a Box M62 Mk1.
Are there any indicators of a colour on the other side of the generator and is there a makers mark visible?