Picric Acid.

A sample of this substance is placed in the Exhibition, prepared from grass-tree resin in the laboratory of the Botanic Gardens. The importance of the gum-resin of xanthorrhœa for varied industrial purposes had not escaped attention. As early as 1845 varnish was prepared from it, the balsamic fragrance of which is remarkably long retained. In a report presented to the Victorian Parliament in September, 1865, it was pointed out that, among the many gratifying results from bringing native vegetable raw material under notice at the Great Exhibition of 1862, one of the more important had been the general recognition of a large percentage of picric acid in the xanthorrhœa resin, this acid being so extensively used as a yellow dye, and on a basis of indigo for green colour. In some of the western parts of Victoria, and particularly in Gippsland and the Western Port district, the Xanthorrhœa Australis abounds on morassy as well as sandy heaths. Other species occur in South Australia, New South Wales, and Queensland, but in West Australia these odd plants form a principal feature in the vegetation—all yield the fragrant resin alluded to, so rich page 35 in picric acid; and in West Australia, therefore, particularly, it ought to become an article of highly-profitable commercial export. Mr. Hoffmann tinged some silks, placed in the Exhibition, with picric dye, prepared by him in the laboratory of Dr. Mueller's department. The discovery of picric acid in xanthorrhœa resin we owe to Dr. Stenhouse, as early as 1845.