LIMESTONE. 333 



quality, as in the small quantity which water can dissolve, it can 

 have little effect, by any chemical agency, in obviating acidity. It 

 is employed too as an astringent in chronic diarrhoea, and in 

 leucorrhcea. Carbonate of Lime, or Chalk (Or eta), is used as an 

 antacid; and Phosphate of Lime has, from theoretical views, been 

 proposed as a remedy in rickets and molities ossium. Muriate of 

 Lime is a more active substance, and more powerful tonic; it is 

 prepared, according to a formula given by the Edinburgh and 

 Dublin Colleges, by decomposing carbonate of lime by muriatic 

 acid, and is obtained in the state of a saturated solution. In its 

 action on the system, it has a considerable analogy to muriate of 

 barytes, and, like it, has been used principally in scrofula and hectic 

 fever, and in dyspepsia. Its dose is 3ss. of the saturated solution ; 

 and, as it is a medicine of considerable activity, it requires to be 

 given with caution. Like other saline substances designed to act 

 on the general system, it is probably most successful when adminis- 

 tered in small doses, with large dilution, as in large doses, and a 

 more concentrated form, its absorption is counteracted, and its action 

 is confined to the intestines." Chloride of Lime, commonly called 

 bleaching powder, is of great importance in the arts, also in medi- 

 cine, and the manufacture of it is carried on upon a very large 

 scale. It is prepared by passing chlorine gas into chambers con- 

 structed for the purpose, in which strata of fresh slaked lime, in 

 fine powder, is exposed to its action, in trays. The gas is absorbed 

 with rapidity, and much heat is evoked. The chloride of lime is 

 thus obtained in the form of a dry white powder, which possesses a 

 faint odour of chlorine, and a strong penetrating taste. It is soluble 

 in water in small quantity ; the solution is decomposed by the dif- 

 ferent acids, even by the carbonic, which it attracts from the atmos- 

 phere, while the chlorine is disengaged slowly, and the carbonate 

 of lime produced. Advantage has been taken of this property for 

 the purpose of arresting the decomposition of animal substances, 

 and of correcting and sweetening the air contaminated with putrid 

 effluvia. Gaseous chlorine has been loner known as having the 

 power of neutralizing the volatile principles given out by bodies in a 

 state of putrefaction, or infectious vapours; but such is the hurt- 

 ful nature of chlorine to respiration, that the greatest caution must 



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