22 AGRICULTURAL CHEMISTRY. 



tlie elements with eacli other are arranged below ; and 

 the figures after each show from which two elements 

 each comes ; while the symbols will show, (when the 

 learner becomes familiar with them), in what propor- 

 tion the elements, in each case, enter into the com- 

 pound. 



TABLE I. 



ELEMENTS. 



1. Oxygen, 0, 8. oxygen compounds. 



2. Chlorine, CI, 36. 1. Chloric acid, ClQs, 76 from 1 and 2. 



3. Sulphur, S, 16. 2. Sulphuric acid, SO^, 40 " 1 " 3. 



4. Phosphorus, P, 32. 3. Phosphoric acid, PO^, 72 " 1 " 4. 



5. Carbon, C, 6. 4. Carbonic acid, C0^ 22 " 1 " 5. 



6. Silicon, Si, 22. 5. Silicic acid, SiO^, 46 " 1 " 6. 



7. Nitrogen, N, 14. 6. Nitric acid, N0«, 54 " 1 « 7. 



8. Hydrogen, H, 1. 7. Water, HO, 9 a ^ u g. 



9. Iron,- Fe, 28. 8. Oxides of Iron,* " 1 " 9. 



10. Manganese, Mn, 28. 9. Oxides of Manganese, " 1 " 10. 



11. Potassium, K, 39. 10. Potash, KO, 47 " 1 " 11. 



12. Sodium, Na, 23. 11. Soda, NaO, 31 "1 " 12. 



13. Calcium, Ca, 20. 12. Lime, CaO, 28 " 1 " 13. 



14. Magnesfum, Mg, 12. 13. Magnesia, MgO, 20 " 1 " 14" 



15. Aluminum, Al, 14. 14. Alumina, AP03, 52 " 1 " 15. 



15. Chloride of Sodium, NaCl, 59 from 2 and 12 



16. Sulphuretof Iron, Fe^Ss, 104^ , " 3 " 9, 



17. Sulphuret of Hydrogen, HS, 17 " 3 " 8, 



18. Light Carburet of Hydrogen, CH*^, 8 from 5 " 



19. Heavy Carburet of Hydrogen, C'^ff, " 5 "- 



20. Ammonia, NH^, 17 " 7 '' 8. 



* There are two oxides of iron, the protoxide and the sesqui- 

 oxide. These are both important in their relations to agricul- 

 ture, and will be explained fully in another place. There are also 

 the protoxide and the peroxide of manganese. 



