Manufacture of Potash. 93 



slightly to red ; ascertain tlie quantity of acid required 

 for saturation, which is generally |- of a fluid ounce 

 to 1 ounce of ashes ; then proceed to filtration through 

 common canvas, washing with plenty of boiling water to 

 carry off the whole of the alkaline salts ; take the insoluble 

 matter from the filtering cloth, dry it, and ascertain the 

 deposition in weight, which will enable you to form an 

 approximate idea of the quantity of alkaline salts or soluble 

 matter contained in the ashes. 



5. Having carefully collected all the washings or lixi- 

 vium together, proceed to evaporation by a slow but regular 

 heat, till the whole of the water is expelled and the nitrates 

 are quite dry; weigh this salt carefully: every 100 parts 

 contain net 48 parts of alkali, which can be proved by 

 proceeding to combustion, when the nitric acid will fly off, 

 and leave the pure potash. 



The she-oak and white gum trees contain the most potash, 

 the proportions being nearly 5- lb. to every 100 lbs. of wood 

 consumed, or 10 lbs. per ton. 



VII. 



On the Manufacture of Potash from Tasmanian Woods. 

 By His Excellency Sir William Thomas Denison. 

 {Read 16 th November, 1849.] 



In a former communication to the Eoyal Society, I gave 

 an account of some experiments which I had requested Dr. 

 Motherwell to make upon the different timber-trees of the 

 Colony, for the purpose of ascertaining the amount of 

 potash contained in them. The results were, as the 

 members of the Society are aware, sufficiently promising to 



