ENRICHINO SOIL— COMMERCIAL RESOURCES 103 



oxperimont, «ni dilferent jmrts of whicli tho 

 various olonionts and (.'onihiiiatioiis of thoni 

 may ho appliod. 



.s(i,(iK.s/t(>.SS t>.\ ('lIAI'TKIi 1/ 



l'J7(i.*An element is a simple sultstance. It is not nuule by a 

 "ombinntion of any other substances, and liy no known means can 

 it be separate*! into any other siiltstances. Siilfnr, nitrojjen, ami 

 phosplionis are elements. The known «<l<<ments number about 70. 



127A. The elements are representeil by one or more letters, 

 failed symbols. Usually the first letter of the name is emi»loyed. 

 Thus, nitro>ren is »lesijfnated by N, jdiosphorus by 1', sulfur by 

 S. When the names of ilifTen-nt elements begin with the same 

 letter, as sulfur and so<lium, this rule cannot be followeil. In 

 -uch cases, lettern from the name of one of the elements in some 

 other lan^ia^e are used. Thus, Na is used for sodium, natrium 

 beinjf the Ijiitiu of sodium. Similarly, I* might represent phos- 

 phorus on pota.ssium ; hence K is used tor ]>otassium, which in 

 I^tin is kalium. 



V.Wii. Compounds r»'sult from the chemical union ('.Wc) of two 

 or more elements. The compound nmy not resemble in any way 

 any of the elements contained in it. The proportions in which 

 i-lementM unite vary, and the same elements may be made to 

 unite in different pro[M>rtion8. The 8amo compound always con- 

 tains the eloments in exactly the same proportion. 



l.'JOfc. (Compounds are represented by writing together the 

 iynilK>ls of tlie elements comi>osing them, togeflier with figures 

 to represent the pro|M>rtions. Thus, potash, K;0, is a compouml 

 "f two parts of potassium and one «»f oxygen, O. Lime, CaO, is 

 se<l of the elements calcium, Ca, and oxygen, and its 

 '■al name is calcium oxid. Other com)MMinds are nitrate of 

 Hoda, NaN<)3 ; ammonia, NIIj (H representing the element hy 

 drogen); water, IIjO ; sulfuric acid, II}SO« ; ammonium nitrate, 

 NH4NO) : ammonium sulfate (NH4)iS04 (the NIIi being taken 

 twice); starcb, ('♦HioOi (C; representing oarlMin); suit. NaCI 

 (CI standing for ohiorin;. 



