THE SULPHUR CURE FOR CALL FORNIAN THISTLE.

Otago Witness, Issue 2086, 15 February 1894, Page 7

THE SULPHUR CURE FOR CALL FORNIAN THISTLE.

The following letter on this subject will be read with interest :— TO THE EDITOB. Sib, — Allow me to thank Mr William Charles Brown for the very warm way in which he has referred to my mode of destroying the Californian thistle. At the same time I hope Mr Brown will forgive me if I should venture to correct what in his remarks I consider a little misleading. He says, seeing that sulphur is insoluble in water, that the destruction caused by Owaka crude sulphur must be through arsenic and other impurities it contains. I beg to say that such is not the case. Sulphur, when converted into sulphuretted hydrogen, is more injurious to vegetation in a given quantity than arsenic. This impurity never is found in Sicilian sulphur. The most ordinary adulteration of precipitated sulphur is with sulphate of lime, of which it frequently Contains from 40 to 50 per cent, Let us

consider for a moment the change that takes place —or in other words, the reaction that sets in — by sulphur coming in contact with water in the nascent state. It readily unites with the hydrogen of the water, giving sulphuretted hydrogen. In this state it is destructive to all vegetable life that it may come in contact witb. Again, 1 may say that it is not correct to say that, after treating the ground with sulphur, grass seed may be sown in a few weeks. It should be 12 months at least when the ground treated may ba ploughed and sown with seed. The flour of sulphur has the same destructive effect, but requires a different mode of application to prove effectual. But just here I would like to say that I have no desire to rush into print and show my want of knowledge in chemistry, or I might be found, like drowning men, ready to catch at passing straws. — I am, &c, John Campbell. Quakerfield, Owaka, February 10.