44 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



sulphur with cupric powders. These powders, such as " Cupro-Calcite," 

 will he dealt with when treating on oidium and mildew. 



Use. — The use of sulphur goes hack to 1846. It was hy rule of 

 thumb that the remedy was first discovered hy the gardener Kyle, 

 in experimenting in the greenhouses of Lyton with mixtures of sulphur 

 and lime. At that time sulphur was already known as capable of 

 curing mildew, and some gardeners used it. But when, in 1848, the 

 oidium appeared, destroying the crops in the neighbourhood of Paris, 

 J. B. Dumas, the Minister of Agriculture, ordered the disease known 

 as Oidium Tuckeri to be examined, and the different remedies recom- 

 mended to combat it to be tested. It was thus that Duchartre, Professor 

 of Botany at the new Agronomical Institute of Versailles, aided by 

 -Hardy, the gardener of the palace, undertook the study of the action 

 of sulphur, and that he decided it to be efficient against the oidium. 

 Gouthier, horticulturist at Montrouge, constructed at this time a bellows 

 for sulphuring, which contributed much to spread the use of sulphur 

 ai'ound Pai'is. Henceforth, owing to this use of sulphur it was pos- 

 sible to contend against the oidium, and in 1852 and 1853 the vines 

 of Chasselas and Thommery were entirely preserved. Sceptical vine- 

 growers, persuaded that the oidium could only develop on perishing 

 vines, sought at the same time a remedy by improving the culture. 

 The good results obtained in 1852, 1853, and 1854, by Lafforgue, Rose, 

 Charmaux, Rendu, and Mares, were disputed by Cazalis Allut, who, 

 after six sulphurings, executed on 140 hectares (350 acres), did not sup- 

 press the oidium. There were long gropings in the dark, unsuccessful 

 years, nevertheless, owing to the persevering efforts and profound 

 study of Mares, a vine-grower of Herault, the action of sulphur on 

 oidium was not long left in doubt. From 1857 sulphuring has spread 

 more and more, and owing to this treatment oidium is no longer 

 propagated to such an extent as to cause serious damage in vineyards. 

 To contend against this disease France alone consumes 100,000 tons 

 of sulphur. 



How does Sulphur' Act ? — The different kinds of sulphur sold 

 in commerce have not the same anticryptogamic value. In a 

 general way that value is proportional to their pure sulphur content 

 and to the fineness of division. Precipitated sulphur and blown 

 sulphur are the products which attain the highest degree of fineness ; 

 sublimed sulphur and ground sulphur come very near them. In the 

 manufacture of ground sulphur great progress has been realized of 

 late years ; formerly, in fact, it required 80 lb. to obtain a result 

 analogous to that got from 40 lb. of sublimed sulphur, whilst now 

 equal weights of these two products have the same anticryptogamic 

 value, The adherence of the sulphur to the leaves depends on its 

 fineness. From this point of view blown sulphur and precipitated 

 sulphur are much superior to sublimed and ground sulphur, but the 

 former are too dear. In extensive exploitations where they used 

 sublimed sulphur almost exclusively, they have begun to replace the 

 latter by ground sulphur, which has the advantage, like blown 

 sulphur, of containing neither sulphuric acid nor sulphurous acid, 

 and thus does not burn the leaves during great heat. To obviate the 



