35 



former being worth about 6d. per lb., the latter double the 

 price. For ascertaining the contents of carbonate of potassa 

 in crude potash or pearlash, certain instruments, well known as 

 alkali-meters, are constructed. The heaviest ashes, as a rule, 

 contain the greatest proportion of potash. The brake-fern, so 

 common on many river banks and sandy tracts of the country, 

 is rich in this alkali. 



Apart from my subject, I may however say, that there are 

 other sources of potash salts than trees alone. Chloride of 

 potassium is obtained from some large salt-beds, for instance, 

 in Prussia: from this source it was supplied to British manu- 

 factories in 1869 to the extent of 154,468 cwt., valued at above 

 60,000. This chloride is besides obtained, under Mons. 

 Balard's process (Report of Juries at the International Exhi- 

 bition for 1862), in considerable quantities from sea- water, 

 as one of the contents to be utilised. From this chloride 

 the various potash salts, otherwise largely obtained from pearl- 

 ash, can. be also prepared. Chlorides and sulphates, if they 

 occur in crude potash, can, in the process of purification, 

 almost completely be removed-.through crystallisation from the 

 greatly concentrated solution. 



Let us now approach another forest industry, one quite 

 unique and peculiar to Australia namely, the distillation of 

 volatile oil from eucalyptus and allied myrtaceous trees. 

 While charcoal, tar, wood-vinegar, wood-spirit, tannic sub- 

 stances and potash, are obtainable and obtained from the 

 woods of any country, we have in Australia a resource of our 

 own in the eucalyptus oil. In no other part of the globe do 

 we find the myrtacese to prevail : in Europe it is only the 

 myrtus of the ancients, the beautiful bush for bridal wreaths, 

 which there represents this particular family of plants; and 

 although copious species of Eugenia and other berry-bearing 

 genera, including the aromatic clove and allspice, are scattered 

 through the warmer regions of Asia, Africa and America, all 

 pervaded by essential oil, they do not constitute the main bulk 

 of any forests as here, nor can their oil in chemic or technic 

 properties be compared to that of the almost exclusively 

 Australian eucalyptus. This special industry of ours exempli 

 fies also, in a manner quite remarkable, how from apparently 

 insignificant experiments may arise results far beyond original 

 anticipations. When in 1854, as one of the Commissioners 

 for the Victorian Industrial Exhibition, held in anticipation 

 of the first Paris Exhibition, I induced my friend, Mr. Joseph 

 Bosisto, J.P., to distil the oil of one of our eucalypts, I merely 



