PHOSPHATE OF LIME. 113 



organic matters containing nitrogen are suffered to 

 putrefy in contact with lime; when animal manure and 

 lime are left together, nitrate of lime is formed ; the 

 same salt is frequently found in the mortar of old 

 walls, particularly those of stables and similar out- 

 houses. When mixed with a solution of carbonate 

 of potash, both salts are decomposed ; nitrate of pot- 

 ash and carbonate of lime being formed. By this 

 process, nitre has often been made in what are called 

 nitre-beds. 



241. Muriate of lime, or, more properly speaking, 

 chloride of calcium, is a very soluble salt, easily formed 

 directly from lime and muriatic acid, and remarkable 

 for its great attraction for water (203). It exists in 

 sea-water, and consequently is often found in common 

 salt. Mixed with a solution of carbonate of ammonia, 

 both salts are decomposed, chalk and muriate of am- 

 monia being formed ; this is remarkable, because those 

 two salts, when mixed together dry, and heated, form 

 muriate of lime and carbonate of ammonia (155). 



242. There is only one other compound of lime of 

 much importance, and which has already been men- 

 tioned ; this is the phosphate. It is found in small 

 quantity in most plants, and forms a great part of the 

 solid matter of the bones of animals (594, 836, 876). 



243. Phosphate of lime is by no means abundant 

 in nature, but it exists in small quantity in a great 

 many substances. Traces of phosphoric acid are 

 found in a great number of rocks and stones, in the 



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