98 INSECTS AFFECTING THE ORANGE. 



SULPHURATED LIME.* A combination of lime and sulphur, made 

 by boiling the sublimate (flowers) of sulphur in milk of lime, is some- 

 times recommended as a u cure-all" for application to orange trees. 

 The preparation contains a mixture of sulphides and sulphates of lime, 

 together with varying quantities of the uucoinbiued ingredients. By 

 continued boiling the action of the sulphur is rendered more complete, 

 and if an excess of lime is present the mixture becomes highly caustic, 

 eating the skin from the hands and destroying the tender leaves and 

 bark of plants. Its preparation is rendered unpleasant and even dan- 

 gerous because of the sulphurous fumes that are given off. 



One part sublimated sulphur, two parts lime, and ten parts water, 

 boiled together half to three quarters of an hour give the best results. 

 After standing a short time the uncombined lime settles to the bottom, 

 leaving a clear yellowish liquid, which, according to the United States 

 Dispensatory, is "an impure aqueous solution of sulphide of calcium, 

 necessarily containing hyposulphite of calcium." 



Under varying conditions higher combinations are formed, and the 

 chemical reactions are exceedingly complicated. 11 A large percentage 

 of the yellowish -green mass consists of insoluble and inert sulphides, 

 but with these are mingled other compounds of lime and sulphur, which 

 give off sulphureted hydrogen gas (hydro- sulphuric acid), and are grad- 

 ually altered by exposure to the air. When, therefore, the mixture is 

 allowed to stand in open barrels, the sulphur compounds part with their 

 active gases, and at length only the caustic action of the lime remains. 



Use in the Orange Grove. As an insecticide sulphurated lime has 

 nearly the same value as potash or soda lye, and in like manner, by its 

 caustic action, it kills the Bark -lice, but does not destroy their eggs, 

 unless it is applied strong enough to injure the bark. 



Its action upon the plant resembles very closely that of potash and 

 other caustics, which are more injurious to the young growth than to 

 the older and less vital parts of the tree. 



The imperfect mixture formed by adding sulphur to lime in the act of 

 slaking is deficient in strength, and has little value as an insecticide. 



Sulphurated lime may prove useful to orange-growers as a destroyer 

 of fungi, and it is advocated as a remedy for foot- rot or other diseases 

 of a similar nature. But these claims, it is proper to state, have not as 

 yet been substantiated by sufficient evidence. 



* The term " sulphurated lime" is here used as a convenience, and is made to include 

 the .various compounds formed by the action of hot water on lime and sulphur. In 

 strictness, the monosulphide (Ca S.) is not formed by the wet process here given. It 

 is thus described : 



"Sulphurated Lime is a grayish- white, or yellowish- white, powder, gradually 

 altered by exposure to air, exhaling a faint odor of hydrosulphuric acid, having an 

 offensive, alkaline taste, and an alkaline reaction. Very slightly soluble in water 

 and insoluble in alcohol. On dissolving Sulphurated Lime with the aid of acetic- 

 acid, hydrosulphuric acid is abundantly given off, and a white precipitate (Sulphate 

 of Calcium) is thrown down." (United States Dispensatory, 1883, page 3*26.) 



