10 BULLETIX 312, U. S. DEPARTMENT OF AGEICULTUEE. 



The apparatus should be set up with the flask supported over a 

 good flame which can be easily regulated, such as that from a large 

 oil burner or from a gas or gasohne burner. The condenser is sup- 

 ported in a vertical position and the bottom side tube connected with 

 a supply of cold water. The column is filled to within 1 or 2 inches 

 of the side tube with glass beads one-haK inch in diameter or with 

 small mipainted baked clay or glass marbles. The hole in the top 

 of the column is fitted vdih a tight cork, tlu*ough the center of which 

 a tube is placed just large enough to admit a common chemical ther- 

 mometer graduated in centigi'ade degi'ees, with the scale reading from 

 100 to 300. This thermometer should be placed tlirough the cork so 

 that the bulb is just opposite the side tube. The flask is then filled 

 a Httlemore than half full of the horsemint oil and the joint between 

 the flask and the column made tight with a leather gasket and clamp, 

 or it may be secured by the use of a ground-joint brass union, one 

 haK of which is brazed to the neck of the flask and the other half to 

 the column. This does av/ay with the use of the gasket, which must 

 be frequently renewed. 



An apparatus of the size described wiU take 15 pounds of oil at a 

 charge and in a day work up 75 to 100 pounds of oil. The cost of 

 construction would be about S50. 



YIELD PER ACRE. 



During the past five yeare areas up to 1 acre in extent have been 

 grown on various soils and as far as possible imder actual commer- 

 cial conditions. The results thus far secured show that an average 

 of 20 pounds of oil per acre from first-year plantings may be regarded 

 as a fair crop, although the test areas have sometimes shown a greater 

 quantity. In succeeding years the yield should be at least 30 pounds 

 of oil per acre, and under good conditions 40 poimds may be expected. 

 Assuming the average phenol content of the oil to be 70 per cent, a 

 figure which is somewhat below the average found for five years, and 

 using the process of manufacture previously described, there may be 

 expected for the first year a jdeld of 12.86 pomids of pure thymol per 

 acre and for the succeeding yeai-s, 19.29 pounds per acre. Taking 

 $2 per pound as the average price of thymol for a period of years, 

 there would be a gross return per acre the first year of .$25.72 and for 

 each succeeding year, $38.58. In addition to this there should doubt- 

 less be added a small amount for the value of the residues, which at 

 the present time has not been determined. 



COMMERCIAL PROSPECTS. 



For many years the commercial source of thymol has been cliiefly 

 the oil of Carum ajowan derived from ajowan seed, wliich is gi-own 

 in the region of northern India and shipped to northern Europe, where 



