80 FARMER'S ASSISTANT. 





lime is combined with phosphoric acid, it is called phos 

 phate of lime. 



Lime, in its pure state, is infusible; but is readily dis- 

 solved in acids, or in six hundred and eighty times its 

 weight of water. When either of the above-mentioned 

 acids is poured on any stone, or earth, which contains lime, 

 an effervescence will take place, by which the presence of 

 this earth may always be discovered. 



Limestone, gypsum, marble, Sec. are generally found 

 the uppermost of the stony incrustations of this globe ; and 

 appear generally to have been formed, before the dry lands 

 appeared. Chemists suppose them to be principally formed 

 frorns hells, such as those with which many parts of the 

 bottom of the ocean now abound, in prodigious quantities; 

 and the skeletons of fishes, and other aquatics, often found 

 in these masses, would in some measure seem to confirm 

 this opinion. 



Some of the stone, commonly called limestone, is com- 

 bined with a large proportion of magnesia; of which earth 

 we shall speak presently. Sometimes, also, limestone is 

 principally combined with argilaceous, and sometimes with 

 silicious, earth; the former being known by its hardness, 

 and smoothness of surface when broken, and is the least 

 calculated to improve a clay soil ; the latter being distin- 

 guished by being more soft, and rough, when broken, and 

 Is best adapted for clays. 



Marble is usually combined with argilaceous earth, and 

 chalk is formed of nearly the same ingredients; but, per? 

 haps, contains less alumine. 



The upland marie is generally a clay, with a certain 

 proportion of lime, and the more the better, as a manure. 

 Sometimes, however, this kind of marie has a considerable 

 proportion of sand ; in which case, it may be found best 

 adapted for clay soils; as, in the former case, it will be 

 found most suitable for those which are sandy. The marie 

 of bog-swamps also varies in its proportions of a fine rich 

 clay, or loam, and of very fine sand; but, in all cases, 

 contains more lime ; and, the weaker sorts, probably, more 

 earth formed of vegetable matter. 

 See further, MANURES. 



There are also calcareous sands, which may be easily 

 discovered by applying any of the acids to them, in the 

 manner before directed. Sometimes, also, these sands are 

 mixed with silex. 



Magnesia is a white, friable, light earth, usually combin- 

 ed with other substances, and sometimes with limestone. 

 When this is the case, the stone, when burned, makes what 

 the English Farmers call hot lime; and, in Greaibriuin, is 



