78 TOBACCO CULTURE. 



(g) Total Phosphoric Acid represents the entire phos- 

 phoric acid compounds without regard to the forms in 

 which they exist. The total phosphoric acid is, therefore, 

 the sum of the soluble, reverted and insoluble forms; or, to 

 state it in another way, the sum of the available and insol- 

 uble forms. 



(//) Phosphoric Acid equal (or equivalent) to Bone 

 Phosphate of Lime is an expression which usually means 

 nothing more or less than insoluble phosphoric acid. 



POTASH, 



(a) Potash, as used in connection with fertilizers, al- 

 ways means a compound containing potassium and oxygen, 

 known chemically as potassium oxide. Potash is never 

 tound as such in fertilizers, but chemists, when expressing 

 the results of analyses use this form as a convenient stand- 

 ard for reference. Fertilizers generally contain potash in 

 such forms as sulphate of potash, muriate of potash, or car- 

 bonate of potash. Instead of stating the amount of sul- 

 phate, muriate or carbonate of potash present in a fertilizer, 

 in giving the results of analyses, its equivalent amount is 

 stated only in the form of actual potash. 



(b) Potash actual is simply another name for potash, as 

 distinct from sulphate, muriate, etc. 



(f) Potash S. (or sul.) means sulphate of potash. This 



is quite often used by manufacturers in giving guarantees. 



(d} Potash soluble represents the amount of potash 



