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INDUSTRIAL AND ENGINEERING CHEMISTRY 725 one application, but the mechanical removal of the material by expansion of the growing parts prevented successful control for so prolonged a period on young, rapidly developing plants. However, application of about 8 pounds per acre of marcasite to the leaves every 2 months has proved a fairly effective means of control in experiments. In order to distribute this small quantity of powdered marcasite, it was mixed with about one-third its weight of infusorial earth. This mixture overcame most of the objections to the handling of marcasite alone. The powdered marcasite itself is somewhat deliquescent and tends to cake on long standing, but the mixture can be handled fairly wrell in a dusting machine. It is doubtful, however, if any treatment will replace the spraying method with pineapples.Recently it has been learned that the treatment for chlorosis with iron sulfides as described above has been largely anticipated by German Patent No. 109,104, granted in 1900 to Cyprien Chateau. This treatment does not appear to have been practiced, however, as no reference has been found in the literature on chlorosis. Application of Marcasite on Sugar CaneCertain small areas of sugar cane on highly calcareous soils in Hawaii show chlorosis of the leaves. Spraying of sugar cane is not very practicable. Application of marcasite to the leaves or in the leaf axils produced a very striking effect, a perceptible greening being noticeable in less than a week. The treated plants resumed normal growth while the adjoining untreated rows remained yellow and stunted. Alexander and Nichols, at Ewa Plantation, Hawaii, found an extremely pronounced increase in growth curves of chlorotic sugar cane when marcasite was applied. The untreated

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