EXPERIMENT STATION. 23 



Potash signifies the substance known in chemistry as potassium 

 oxide, which is the valuable fertilizing ingredient of " potashes " 

 and " potash salts." It is most costly in the form of sulphate, and 

 cheapest in the shape of muriate or chloride. 



Jlie Valuation of a Fertilizer signifies estimating its worth in 

 money, or its trade-value ; a value which, it should be remembered, 

 is not necessarily proportional to its fertilizing eifects in any special 

 case. 



Plaster, lime, stable manure and nearly all the less expensive 

 fertilizers have variable prices, which bear no close relation to 

 their chemical composition, but guanos, superphosphates and other 

 fertilizers, for which 830 to $80 per ton are paid, depend chiefly 

 for their trade-value on the three substances, nitrogen^ phosphoric 

 acid and potash^ which are comparatively costly and steady in 

 price. The money-value per pound of these ingredients is easily 

 estimated from the market prices of the standard articles which 

 furnish them to commerce. 



The average Trade-values^ or cost in market per pound, of the 

 ordinarily occurring forms of nitrogen, phosphoric acid and pot- 

 ash, as found in the Connecticut and New York markets, and 

 employed by the Station during 1881, have been as follows: 



Trade-Values for 1881. cents per pound. 



Nitrogen in nitrates, 26 



" in amoiouia salts, -. 21\ 



" in Peruvian Guano, fine steamed bone, dried and fine ground blood, 



meat and fish, superphosphates and special manures, 20 



" in coarse or moist blood, meat or tankage, in cotton seed, linseed, 



and Castor Pomace, 16 



" in fine ground bone, horn and wool dust, 15 



" in fine medium bone, 14 



" in medium bone, 13 



" in coarse medium bone, - 12 



" in coarse bone, horn shavings, hair and fish scraps, 11 



Phosphoric acid soluble in water, \1\ 



" " " reverted " and in Peruvian Guano, _ 9 



" " insoluble, in fine bone and fish guano, 6 



•' " " in fine medium bone, . 5^ 



" " " in medium bone, 5 



" " " in coarse medium bone, 4|- 



" " " in coarse bone, bone ash and bone black, 4 



" " " in fine ground rock phosphate, _3-|- 



Potash in high grade sulphate, 7-J- 



" in low grade sulphate and kainite, 5J- 



" in muriate or potassium chloride, 4^ 



