THE FARMER AT HOME. 39 



specific gravity with the liquor itself, that mere rest will not effect a 

 separation. In these, too, the liquor is generally rendered thicker 

 than usual hy holding in solution much mucilage, which further 

 entangles the turbid matter, and prevents it from sinking. Hence it 

 is that vinous fermentation has so powerful an effect as a clarifier, 

 since this process always implies the destruction of a portion of sac- 

 charine mucilage, and the consequent production of a thin limpid 

 spirit. 



Coagulating substances are great clarifier s when mixed with any 

 turbid liquors, the process of coagulation entangling with it all mat- 

 ters merely suspended and not dissolved, and carrying them either to 

 the top in the form of a scum, or to the bottom in the form of a thick 

 sediment, according to circumstances. Thus, to clarify muddy cider, 

 the liquor is beaten up with a small quantity of fresh bullock's blood, 

 and suffered to stand at rest for some hours, after which the liquor 

 above is as clear as water, and almost as colorless, and at the bottom 

 is a thick tough cake, consisting of the coagulated blood which has 

 carried down with it all the opaque matter suspended in the liquor. 

 Albuminous and gelatinous substances act in the same manner. The 

 effect of white of an egg in this way is known to every one. It 

 should be first mixed with the turbid liquor, without heat and by 

 agitation. Afterwards, on applying less than a boiling heat, the 

 albumen of the egg coagulates, and carries up with it all the opaque 

 particles, leaving the rest beautifully clear and limpid. Sometimes 

 clarification takes place in a very unaccountable manner. Thus, it 

 is well known, that a handful of marl or clay will clarify a large cis- 

 tern of muddy water, and marl is also used with advantage in clarify- 

 ing vinous liquors. 



CLAY. There is a great variety of earths or clays denominated 

 after the particular use to which they are applied, as Porcelain Clay, 

 which consists of alumina and silex, with a little mica, and is found 

 in Cornwall, Saxony, Japan, and China. It is of a reddish white, is 

 supposed to be formed from the decomposition of felspar, and is used in 

 the manufacture of porcelain or china. Pipe Clay is of a greyish or 

 yellowish white. Potters' Clay is found of various shades of yellow, 

 grey, green, and blue. The most durable kind of bricks are made of 

 a Yellow Clay containing some iron, and a considerable portion of 

 silex. 



Next to silicia, common clay is the most abundant of the earths, 

 and is of extensive service to the agriculturist. Indeed without its 

 presence, vegetation would scarcely be possible, and cultivation could 

 not exist. To the presence of clay we owe the capacity of soils to 

 retain moisture in any degree, since the other earths would leave it so 

 porous, that water would pass through it as readily as through a 

 sieve. Mixed with lime, clay constitutes marl, of which such use is 

 already made in fertilising the soil, where these ingredients appear to 



