DESTROYING STUMPS.

Waipa Post, Volume IV, Issue 153, 11 October 1912, Page 4

DESTROYING STUMPS.

USE OF SULPHURIC AND NITRIC ACIDS. The following paragraph is taken from the Agricultural Gazette of New South Wales : Mr C. Maud, Erina, Gosford, informs the Department that a neighbouring farmer has been very successful in destroying stumps with a mixture of sulphuric and nitric acids. In treating a swamp mahogany stump, 3ft 6in in diameter, 6d worth of acids were put in an auger hole, and in five weeks’ time the whole stump and roots had so rotted that they could be knocked to pieces with a hoe. Mr Maud states that a stump 3ft in diameter would take about half a pint each of the acids, and a smaller one less. The acids are used in equal quantities, and nothing is. added to them. A hole is bored in the stump with a 2-inch auger, deep enough to hold the quantity of acids to be used, and then one acid is poured in and the other added. The hole is then plugged air-tight with a wooden plug. Not more than one pint of acids (half pint of each) would be mixed at one time. Mr Maud asks whether there is any danger in this, and what is it.

“Mr F. B. Guthrie, chemist of the Department, reports as follow.^:— “ There should be no risk attending the mixing of the above quantities, provided the sulphuric acid is added to the nitric acid, and uni vice versa. There is a certain amount of risk in mixing nitric and sulphuric acids on account of the heat evolved and the consequent danger of spirting. There is not likely to be any danger in mixing small quantities in this manner, but with larger quantities the mixture will get very hot on the first addition of the sulphuric acid, and must be allowed to cool before the remainder is added ; otherwise the-action is very violent. Both the acids separately are extremely corrosive and must not come into contact with the person or clothing. With dry wood, nitric acid forms into nitro-cellulose, which is an explosive, but there is not much risk of this substance being formed under the conditions. Put the nitric acid in the hole first, then add the sulphuric acid.”