ESSENTIAL OILS 175 



The apparatus required for the distillation of lemon-grass oil does not 

 differ from that in general use for the distillation of other volatile oils. 

 Before distilling the plants it has been found advisable to run them 

 through a fodder cutter, in order to permit closer packing in the retort. 

 From the data at hand it is estimated that if the plants are cut into 2- 

 inch lengths a retort will hold 100 pounds of material for every 6 cubic 

 feet of space, but if the plants are put in w^hole the quantity w^hich the 

 retort can hold will be somewhat less. The closer packing, however, in no 

 way facilitates distillation. 



In a retort having a capacity of 30 cubic feet a charge of 3,000 pounds 

 can be distilled in 2 to 21 hours by the steam which may be readily gen- 

 erated in a small farm boiler, and by the use of a larger volume of steam 

 the time can be much reduced. 



After the oil has been distilled it should be freed from water so far as 

 possible in a separatory funnel, then dried by shaking with anhydrous 

 calcium chloride, and filtered. It should be stored in well-filled air-tight 

 containers in as cold a place as possible until ready to be shipped to 

 market. The shipping can be done in new and clean tin cans without 

 injury to the product. 



Leach,* in discussing lemon extracts, states: 



The flavor of the cheap extracts is sometimes reinforced by the addi- 

 tion of such substances as citral, oil of citronella, and oil of lemon grass, 

 but minute quantities only of these pungent materials can be used, not 

 exceeding 0.33 per cent in the case of citral, and 0.1 per cent in the case 

 of the two last mentioned oils. 



According to Askinson,t essence of lemon grass consists of 

 2 ounces of lemon-grass oil dissolved in 1 gallon of alcohol. 



Lemon-grass oil consists largely of citral and contains also 

 small quantities of various substances such as methyl heptenone, 

 and the terpenes, limonene and dipentene. The exact value of the 

 oil depends chiefly upon the amount of citral it contains. High- 

 grade oils contain about 70 to 80 per cent of citral. This is 

 an aldehyde which occurs not only in lemon-grass oil, but also 

 in lemon oil (the oil obtained from lemon peel) and in many 

 other natural essential oils. 



Bacon investigated lemon grass grown at the Government ex- 

 perimental station at Lamao, Bataan, in unfertilized soil. Con- 

 cerning his results on these plots of grass he states : 



Lamao. — Planted February 14, 1908. First cutting July 29, 1908. Ob- 

 tained 432 kilos grass, from 57 square meters of ground, distilled two days 

 after cutting, the yield was 900 grams of oil (0.2 per cent) of the following 



properties: Specific gravity, ^^- =0.894; N^ =1.4857; A^^' = +8.l; 



citral = 79 per cent; Schimmel's test passes the oil. 



* Leach, A, E. Food inspection and analysis (1914), page 872. 

 t Askinson, G. W., Perfumes and cosmetics, page 161. 



