364 Journal of Agriculture , Victoria. [ioth June, 1912. 



that a suitable article will be supplied. The illustration given here is for 

 a small still about twenty-five (25) gallons. The design can be made to 

 kny size required. 



The treatment of the various plants from wh'ch oil is extracted by dis- 

 tillation is carried out in the same manner as the product now under 

 consideration. There is one thing very necessary when changing from 

 one product to another — a thorough deodorizing and cleaning must 

 take place, otherwise much of the product will be destroyed. 



DiSTiLLING. 



This operation is looked upon as being .somewhat difficult, but it only 

 requires a little practice to get good results. It may be mastered by the 

 most inexperienced person with a few trials. 



The oil contained in the leaves and stems is lighter than water, and 

 it has also a lower boiling point. When heat is applied the 

 oil rises and passes off with a little steam before the boiling 

 point of the water is reached. The finer and better part of 

 the oil escapes first, and here it is that care and skill is required to make 

 the most of the product, and to secure a first and second quality of oil. 



The steam, water, and oil which passes through the condenser referred 

 to, passes out through the lower portion of the cooling tank into a receiver 

 known as the " Florentine." This somewhat resembles a teapot without 

 a handle. The oil and water dropping into the top of the receiver 

 separate, the oil floating on the top whilst the water escapes slowly at 

 the spout. As the outlet is at the bottom of this receiver and the top of 

 the spout a little below the mouth or level of the receiving portion of the 

 " Florentine," the water and oil are separated. 



One mistake frequently made is in forcing the distillation. The boiling 

 should be .slow, so as to avoid forcing over objectionable matter. A tank 

 of 400 gallons should be allowed four or five hours to boil ; after the 

 first two hours the receiver should be changed, as the oil to follow is of 

 secondary quality, and should be marketed separately. It is said that 

 whatever oil the stalks contain is inferior in quality, and, being the last to 

 be driven off, the heat must be regulated and the boiling a simmer only. 



In distilling, it is much preferable to heat the water in the boiling 

 tank with superheated steam, as it is more under control. This is done 

 by having a steam generator close by, and running steam through a per- 

 forated coil placed in the bottom of the still. The heat can then be regu- 

 lated to a nicety. Some eucalyptus distillers run hot steam through their 

 leaves without water, but this does not meet with general approval for 

 the finer essential oil plants. When applying direct heat greater attention 

 is required than in using steam. 



Yields and Prices. 



A good crop of well-established mint will yield from five to six tons 

 per imperial acre. As to the yield of oil, some growers give 3 to 4 lb.;, 

 per ton, whilst others state 5 to 6 lbs. ; nothing definite can be given in this 

 respect. At the DunoPly and Leongatha Government Scent Farm mint 

 was the last crop to receive attention, and it was riot sufficiently estab- 

 lished to give any reliable data to quote from. 



