86 PRACTICAL FARM CHEMISTRY. 



profitable to buy, especially if they have to be 

 freighted any considerable distance. 



The manufacturer has to charge for all the goods 

 that he delivers at buyer's nearest station: 



(1) Retail price of the plant foods, as given in the 

 schedule of prices previously mentioned. 



(2) Cost of preparing and mixing these raw ma- 

 terials, and of storing and handling the goods. 



(3) Cost of bags, barrels, etc., and putting up in 

 ship -shape. 



(4) Freight, cartage, etc. 



For a number of years I have used a special 

 potato manure with most gratifying results. This 

 is a ''high-grade" mixture, containing about four 

 per cent nitrogen, twelve and half per cent phos- 

 phoric acid, and six per cent potash. Now suppose 

 we wish to buy 80 pounds of nitrogen,. 250 pounds of 

 phosphoric acid and 120 pounds of potash, which is 

 just about the quantity contained in one ton of a 

 high-grade potato manure. Computed at schedule 

 rates, this quantity of plant foods, in the form they 

 appear in the potato manure (partly soluble and 

 partly not), would have a chemical value of about 

 thirty-four or thirty-five dollars. To this, the 

 manufacturer adds expense of handling, mixing, 

 bagging, carting, freighting — and perhaps some- 

 thing for profit — charging about forty-two dollars 

 per ton, or an advance of about seven or eight dol- 

 lars per ton, or somewhat over twenty per cent of 

 the value of the raw materials. 



Another manufacturer might offer us a low-grade 

 or ''cheap" fertilizer having just one-half of the per- 

 centages of plant foods contained in this potato 

 manure. To get the same quantities of the food 

 elements, two tons of the cheaper kind would be re- 



