BOOK VI. 



A — Machine first described. B — This workman, treading with his feet, is com- 

 pressing THE bellows. C — Bellows without nozzles. D — Hole by which heavy 

 vapours or blasts are blown out. E — Conduits. F — Tunnel. G — Second 



MACHINE described. H — WoODEN WHEEL. I — ItS STEPS. K — BARS. L — HOLE IN 



same WHEEL. M — Pole. N — Third machine described. O — Upright axle. 

 P — Its toothed drum. Q — Horizontal axle. R — Its drum which is made of rundles. 



