FARMER'S ASSISTANT. 79 



For dying the scarlet, three parts of water to one of so- 

 lution of tin, are to be mixed together; and then such a 

 quantity of cochineal must be added, as will just give the 

 scarlet hue ; and, if a still paler red is wanted, the quantity 

 of Cochineal and mordant must be reduced. 



To give a dark and unchangable blue color to wool (says 

 Mr. Genet, from whom we derive most of the information in 

 this article) the French Manufacturers mix one part of the 

 best indigo, pulverised, with eight parts of vitriolic acid ? 

 well concentrated, and leave it undisturbed for twenty-tour 

 hours. They then add, by degrees, ninety-six parts of pure 

 soft water to the mixture, and stir it frequently. 



If the wool, or cloth, when immersed in this, becomes of 

 too dark a blue, its color is to be made lighter by its being 

 soaked about a day, or a longer or shorter time, as may be 

 found necessary, in a cold solution of twenty-four parts of 

 pure soft water and one of sea or common salt. 



Allum, says Mr. G- may be used as a mordant for indi- 

 go; and if any woolens are immerged in a bath containing 

 a solution of soda, after being dyed with this blue, and 

 fixed with this mordant, they will acquire a darker color. 

 The same method, he says, may be successfully applied to 

 silk, but not to linen or cotton. 



E. 



EARTHS. Chemists, by analysing the substance which 

 forms this earth, find it to contain several distinct kinds of 

 matter, which they denominate primitive earths; which 

 are, however, unnecessary to be designated here, farther 

 than as some of them enter into the composition of soils. 

 These are principally lime, magnesia^ silex^ and alumine. 

 In addition to these, other substances are found in soils; 

 such as animal and vegetable matter, in a decomposing 

 state, certain saline compounds, and the oxoyde of iron. 



Lime is seldom found in its puri(y; but is generally 

 combined with other earths, and with acids. What are 

 commonly called limestone, marble, chalk, and the differ- 

 ent kinds of marie, are all mixtures of lime with other 

 earths, combined with carbonic acid, and are each called 

 carbonates of lime. 



Gypsum, or sulphate of lime, is a mixture of lime with 

 other earths, combined with sulphuric acid; and, when 



