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vegetables. When it combines with other bodies, it forms substances 

 called chlorides. Common salt is a chloride of sodium. Every lOOibs. 

 of salt contains upwards of 60 ibs. of chlorine. It rarely exists in nature 

 in a free, or uncombined state ; it is not known, therefore, to exercise 

 any direct action upon the general vegetation of the globe. It is thought 

 to be more important to animals than to vegetables. It is not present 

 in any very great amount in vegetables, but when present it is rather in 

 the stalks and leaves than in the seeds. Clover, hoAvever, has some 

 considerable chlorine, and wheat less. It is quite probable, however, 

 that there is more chlorine present in growing plants than is found in 

 their ashes ; as the burning of them to obtain the ash, would drive off 

 the chlorine. 



Sulphuric Acid. — This is the common oil of vitriol of the shops. 

 It is a compound of sulphur and a gas called oxygen. It is rarely met 

 with in nature, in an uncombined state ; but is generally found united 

 with potash, soda, magnesia or lime ; the latter of which is the common 

 plaster or plaster of Paris, which is so much used as a fertilizer. This 

 substance is called sulphate of lime by the chemists. In every 100 Bbs. 

 of plaster of Paris, there are about 33 Bbs. of sulphuric acid. Epsom 

 salts is also a composition of sulphuric acid and magnesia. Sulphuric 

 acid, although it is seldom if ever found as such in vegetables, yet it is 

 an important element of soils. Sulphur, one of its elements, is often 

 found in plants, such as peas and beans, and indeed in almost all plants 

 of this kind. It is also found as an essential ingredient in horse radish, 

 cabbages, mustard, &c. Whenever sulphur is absent in the soil, it has 

 to be supplied by the farmer, by some artificial means ; as for example, 

 by plaster of Paris, or sulphuric acid itself, very much diluted by water. 



Phosphoric Acid. — This substance is not one that is often seen of itself 

 by the farmer. It is a combination of phosphorus and oxygen, just as 

 sulphuric acid, or oil of vitriol, is a combination of sulphur and oxygen. 

 Most persons are familiar with phosphorus as it is seen in the shops of 

 the druggists. When phosphorus is burned in the air, phosphoric acid 

 fumes will be seen to rise. This is seen in the fumes of a match before 

 the sulphur takes fire. This substance, in its various combinations with, 

 other bodies, is of great importance in the vegetable economy, and of 

 course is an essential element of soils. In the parts of plants used for 

 the food of man, it is found in the greatest abundance. It seems to be a 



