39 



The optical rotation of the first fraction a D + 27-85, and of the second fraction 

 a D + 22-35, so thai dextropinene forms the greater portion of the oil of this 

 species. The nitrosochloride was prepared and this melted at the correct 

 temperature for that substance. 



Material of this species was also collected at Hurstville, N.S.W., in 

 June, 1898. The oil was almost identical with the above and consisted principally 

 of dextropinene. The specific gravity of the crude oil = 0-8774. The saponi- 

 lication number for the esters and the free acid was 15-2. The crude oil required 

 9 volumes 80 per cent, alcohol to form a clear solution. The trees at Milton 

 were growing in granite formation, and those at Hurstville in the Hawkesbury 

 sandstone country., so that the constituents of the oil of this species are com- 

 paratively constant, irrespective of the geological formation upon which the 

 trees grow. 



10. Eucalyptus robusta. 



(Sm., in Bot. Nov. Holl., pp. 39-40, t. 13.) 

 Swamp Mahogany. 



Systemr lie. A fairly large tree, with reddish, brittle bark between a 

 " Stringybark " and a " Bloodwood " bark. Leaves large and coarse, leathery; 

 lateral veins n imorous, straight and parallel; intramarginal vein prominent, close 

 to the edge. Venation thus indicates pinene in the oil. Peduncles axillary, 

 thick, flattened, about i inch long. Flowers large. Calyx turbinate and green ; 

 operculum cream-coloured, rostrate and slightly larger and broader than the 

 calyx tube. 



Fruit. Urceolate ; rim bevelled ; valves well sunk ; 

 only rarely exserted ; 9 lines long, including 

 the pedicel. 



A decidedly distinct fn/il with its sharp-edged rim and 

 sunken horizontal valves. 



Habitat. Coastal swamps of New South Wales and South 

 Queensland. 



REMARKS. A tree easily identified by its comparatively large fruits and by its large, coarse leaves, and 

 habitat, being rarely, if ever, found growing away from low, swampy ground. The timber is red-coloured, hard 

 and durable. 



ESSENTIAL OIL. Leaves and terminal branchlets for distillation were 

 obtained from La Perouse, near Sydney, in August, 1900. The yield of oil 

 was 0-16 per cent. The crude oil was red in colour, and had a turpentine-like 

 odour. It consisted largely of pinene ; phellandrene was also detected, but 

 this constituent was only present in a very small amount. Only a trace 'of cineol 

 could be detected in the second fraction. The oil distilling at near 270 C., 

 consisted mostly of the sesquiterpene. 



The crude oil had specific gravity at 15 C. = 0-8777 '> rotation a D + 4-0 ; 

 refractive index at 20 = 1-4744, an d required 8 volumes of 80 per cent, alcohol 

 to form a clear solution. The saponification number for the esters and free acid 

 was 9-1. 



