192 VEGETABLE SUBSTANCES. 



pitch, then only 300 cwt. would be obtained ; but 

 the evaporation if carried thus far will char the 

 extract, which must on every account be avoided, 

 since its tanning properties are then entirely de- 

 stroyed. A ton of the best white oak bark produces 

 500 cwt. of extract, two-thirds of which is pure 

 tannin ; of the entire bark less than one-seventh of 

 its weight is extract, half of which only is pure 

 tannin. The mimosa is therefore rather less rich in 

 tannin than oak bark, but where it so abounds this 

 difference is not of any importance. Five tons of 

 this extract sent from Van Diemen's Land were 

 also favourably received. This extract was prepared 

 rather differently, being boiled for twelve hours and 

 then strained ; then boiled for twenty-four hours and 

 strained, and again boiled for an equal time arid again 

 strained. 



The wattle bark, in its unprepared state, has been 

 shipped to this country in small quantities, and the 

 advantage arising from its importation in the form 

 of an extract, has induced those persons interested in 

 the subject to engage the attention of some of the 

 first chemists in its examination and preparation. 

 Professor Davy, of the Royal Dublin Society, has, in 

 consequence, very recently prepared from the bark 

 a dry extract by the employment of a new method 

 of evaporating, by means of which the extract cannot 

 by any possibility be charred. The adoption of this 

 simple method in Australia would ensure the importa- 

 tion of the substance in a state uninjured for use ; 

 while in the solid form its transport will, in every 

 way, be less expensive. The present price of 

 mimosa, or wattle bark, is 7 to 7. 10s. per ton. 



In the third volume of the Gardener's Magazine 

 it is stated, that " the pods of the Ccesalpinia 

 coriaria, known by the common names of Dividivi, 

 or Libidibi, are used by the inhabitants of Cura^oa, 



