520 R. T. BAKER AND H. G. SMITH. 



Yield of Oil. 



The yield of oil from the Yourie-Tanto material agrees 

 with that of this species from other localities, and our 

 sample, distilled at the Museum, gave 4*4% for leaves with 

 terminal branchlets, collected in the month of November, 

 when the temperature is usually high. The material, 

 which had dried somewhat, was weighed into the still and 

 the amount of oil correctly determined. These figures may 

 perhaps be considered as the maximum yield. The greatest 

 quantity of oil from most species of Eucalyptus is obtained 

 during the summer months, and the least yield during the 

 winter. From a series of results obtained by Mr. E. 

 McGrath of Yourie, during the months of June, July, August, 

 September and October, these differences are strongly 

 brought out. Mr. McGrath uses a pair of tanks coupled 

 together and worked at the same time. These tanks are 

 the usual 400 gallon square iron tanks fitted in the simple 

 manner customary with the majority of Eucalyptus oil 

 distillers in New South Wales. During the month of June 

 the average weight of oil he obtained from the two tanks 

 was, first hour oil 28 lbs., second hour 12 lbs., or an average 

 per tank for each distillation of 20 lbs. During July the 

 average yield was, first hour 37 lbs., second hour 11 fibs, or 

 an average yield per tank per distillation of 24 fibs. During 

 August the average yield was, first hour 39 lbs., second 

 hour 12 fibs., or a yield of 25-§- pounds per tank per distilla- 

 tion. During September the average yield was, first hour 

 42 lbs., and second hour 12 lbs., or 27 lbs. per tank per 

 distillation. For twenty-two days in October the average 

 yield was 41 lbs. for first hour, and 11 fibs for second hour, 

 or an average per tank per distillation of 26f fibs. 



The actual weight of green leaves with terminal branch- 

 lets packed into the tanks was not taken, but if this weight 

 be considered as 800 fibs, per tank, which as an average 



