THE CITRINE ODOURS. 69 
interior surface of which is studded with a large number of 
metallic knife-points. This cylinder revolves on two axles attached 
Fig. 6. 
to it at diagonally opposite points. Its capacity is such that when 
charged, as indicated in the illustration, it is capable of holding 
1200 or 1500 lemons. The cylinder having been properly charged, 
say with the above-mentioned number of lemons, together with a 
small quantity of water, it is set in motion by aid of the shafting 
and pulleys driven by the small steam-engine. The fruits are 
thereby made to come in contact with the metallic lancets, 
and their whole surface gradually becomes punctured sufficiently 
to cut or rupture the cells containing the essential oil, which 
escapes. The cylinder A has double walls, the space between them 
being intended for the circulation of a current of steam, which is 
admitted to heat the water and to facilitate the extraction of the 
oil, while at the same time the vapours are rarefied or aspirated by 
the vacuum-pump L. The axles of the cylinder on both sides are 
hollow : that on the side looking towards the engine is imbedded 
in such a manner that steam from the boiler may be admitted 
at will either into the double walls of the cylinder or into the 
interior of the cylinder itself; while the hollow passage in the other 
axle communicates with a condensing-worm, the outlet of which 
(H) descends into a cylindrical vessel I, intended to receive the 
condensed products, consisting of water and essential oil. When 
