(thanks to David Butler for preparing the coloured version of the drawing)
The Old StillThe woodcut of the still has appeared in a variety of sources. Stills of this vintage varied widely in the quality of their construction but an important ingredient tended to be the ease with which they could be carried or hidden. For this reason, Excise rules later stipulated a minimum allowable size of still, specifically one that was too big to move around.
I'm not going to claim a definitive guide to the drawing till I've checked but "B" will contain the lower half of the pot. Why it is shaped that way I'd have to guess - it could be there's an outer flame guard or perhaps it is easier to make that way (remember the still will need to be opened to clean and refill). The neck of the still is visible at "A" and the vapour will rise and go down the lyne arm. What I don't see is a condensing "worm" which would be a coil of several turns of copper pipe in a barrel of water attached to the end of the open pipe in the drawing.
The various bits of copperwork were highly prized and a disaster if seized by the Excisemen. jhb