328 ODOROCxRAPHIA. 



obtained from wood cut in the summer months. The wood is cut 

 into lengths of from one to six inches by a chopping machine ; 

 this consists of two strong, heavy knives about eighteen inches 

 long and three to four inches wide, fastened to one end of a shaft, 

 the other end being connected by a wheel and belting with a 

 water-wheel. The wood is pushed under the knives by hand, 

 throusfh a box or trough similar to that of a chaff-cutter. For 

 every revolution of the shaft the knives make four cuts, and it 

 requires but a short time to cut a ton of the material. The still 

 consists of a heavy wooden box, eight feet long, four feet wide and 

 four feet deep, with a copper bottom and stayed by bolts. The 

 head of the still is of copper. The whole affair rests on a stone 

 foundation 15 to 18 inches above the surface of the earth, a place 

 being made for a fire ; wood alone is used for fuel. The still is 

 filled with the pieces of birch to within twelve inches of the top, 

 and sufficient water is let in to cover it. This is allowed to 

 macerate from eight to twelve hours ; the fire is then started and 

 the distillation carried on for eight and sometimes ten hours, but 

 during the first two hours 90 per cent, of tlie oil has passed over. 

 As the liquid comes from the condenser (which is of the common 

 type) a novel contrivance is used for collecting the oil ; this 

 consists of a 2-quart fruit jar, fitted with a cork having two holes ; 

 a small funnel is put into one of the holes so that the end of it is 

 about two inches below the bottom of the cork, and connected 

 with the other hole is a suitable pipe formiug an outlet. The 

 distillate passes through the funnel into the receiver, where the 

 water and oil separate, the oil going to the bottom, being heavier, 

 and the water flowing away through the pipe into a larger 

 receiver, where it is reserved for the maceration of the next 

 quantity of birch to be distilled. When the distillation ceases, the 

 crude oil, containing a little water and fragments of vegetable 

 matter, is emptied into a can with a broad flat spigot fastened as 

 close as possible to the bottom ; the impurities float on the surface 

 and the clear oil is then drawn off' through the spigot. The oil is 

 afterwards rectified. The oil is also distilled by placing the 

 material in a wooden vat and passing steam through it from a 

 separate boiler. 



Wintergreen oil and Birch oil is now distilled on a large scale 

 in new Jersey by chemists who, by employing a modern system of 

 distillation, obtain a finer product, a 'perfectly colourless oil, and also 



