22 ESSENTIAL OILS FROM THE 



from which this oil is extracted is very plentiful, and widely distri- 

 buted. It inhabits vast tracts of swampy and often sub-saline country, 

 and gives rise to the term "Tea-tree Swamp ;" it is remarkable for 

 growing actually in water. It is also found in Tasmania and New 

 South Wales, seldom exceeding the size of bushes, and penetrates along 

 the watercourses into the ranges. It could be collected in very large 

 quantities without difficulty. The minuteness of its leaves renders it 

 necessary to introduce the smaller branches with them into the still, so 

 that the yield of oil, which amounted to 5 ounces from 100 lbs. of fresh 

 material, is, therefore, much less than it would be, could the leaves be 

 operated on alone, as they do not constitute more than about a fourth 

 of the weight of the whole. This remark is true of many of the plants 

 of this genus, but more especially so of the ericifolia, as its leaves are 

 smaller than those of any other, samples of the oil of which have been 

 forwarded to the Exhibition ; it may also help to account for the 

 very great difference in the quantity obtained by each of the exhi- 

 bitors. 



The oil bears a striking resemblance to the cajeput of commerce, 

 obtained from the Melaleuca leucadendron of the Moluccas. The colour 

 of the product from this species of tea-tree is a very pale yellow ; its smell 

 is like cajeput, but somewhat less agreeable ; its taste is bitter and 

 camphoraceous, followed by a cool sensation, like that produced by 

 peppermint, but the similarity to camphor is less perceptible, both in 

 smell and taste, than it is in cajeput. This volatile oil is thin, but not 

 as mobile as others ; its specific gravity is - 899 to 0"902, at 60° F., 

 and it boils freely at about 300°, the mercury rising to 362°. In 

 shallow vessels it is as difficult to ignite as any of the preceding oils from 

 the genus Eucalyptus, but in a common kerosene lamp it burns 

 very well, with a dense white flame, giving rise to neither smoke nor 

 smell. 



When iodine is broiight into contact with it, at ordinary tempera- 

 tures, reddish fumes are perceptible, without any explosion ; by raising 

 the temperature, variegated vapours are emitted similar to those already 

 described. 



It is worthy of remark, that the distillation of cajeput from the 

 leaves of the Melaleuca leucadendron is conducted in a manner differing 

 from that which has been pursued in the production of the Victorian 

 oils, as in that case the leaves of the plant are allowed to heat in sacks, 

 and are subsequently macerated in water, and fermented for a short time 

 before the distillation is commenced. The object of this treatment is 

 probably to increase the yield, and facilitate the escape of the oil ; but 

 it should be remembered that the productiveness of the M. leucadendron 

 is not large — viz., scarcely three drachms from two sacks full of leaves ; 

 while the yield from M. ericifolia, and one or two other species, must be 

 at least from twenty to one hundred times as great. It will be seen from 



