New York Agricultural Experiment Station. 129 



Potash. 



{a) Potash, as used in connection with fertilizers, always means a 

 compound containing potassium and oxygen, known as potassium 

 oxide. Potash or potassium oxide is never found as such in fertil- 

 izers, but chemists use this form of expressing the results of analysis 

 as a convenient standard for reference. Fertilizers generally con- 

 tain potash in such forms as sulphate of potash, muriate of potash 

 or carbonate cf potash. Instead of stating the amount of sulphate, 

 muriate or carbonate of potash present in a fertilizer, its equivalent 

 amount is stated only in the form of potash in giving the results of 

 analysis. 



(b) Potash Actual is simply another expression for potash, as dis- 

 tinct from the sulphate, muriate, etc. 



(c) Potash S. (w Sul.) means sulphate of potash. This is quite 

 often used by manufacturers in giving guarantees. It is very mis- 

 leading and, when used, is evidently employed for the purpose of 

 making purchasers think that it is actual potash. One pound of 

 potash is equivalent to 1.85 pounds of sulphate of potash ; and so, in 

 stating a guarantee as sulphate, the manufacturer makes it appear 

 that his goods contain more potash than they really do. 



{d) Potash Soluble represents the amount of potash that dissolves 

 in water and is available for the use of the plants. The different 

 forms of potash commonly used in fertilizers are readily soluble in 

 water. 



{e) Potash as Suljphate means simply sulphate of potash. 



(y) Potash equal {or equivalent) to Sulphate of Potash is an 

 expression which means simply sulphate of potash. When the 

 potash is present as muriate, this expression should never be used. 



{g) Sulphate of Potash signiiies, or should signify, that this com- 

 pound is actually present in the fertilizer and there is no muriate of 

 potash present. 



(A) Potassium Oxide means the same as potash or actual potash. 



2. Total Constituents of Fertilizers. 



If we add together the figures representing the different constitu- 

 ents of a fertilizer (the nitrogen, the total phosphoric acid, and the 

 potash),' we shall find, as a rule, that the sum amounts to only 20 or 

 30 per cent, or pounds per hundred. The question often arises, 

 " Why does the sum of the constituents in the analysis of a fertilizer 

 9 



