168 IMPORTANCE AND VALUE 



not been entirely passed over, inasmuch as they are 

 included in the estimate given for the salts of potash . 

 and soda, and also for gypsum ; in the first case, it is 

 granted, for the sake of simplicity, only in the lump. 

 Much might, indeed, be far more strictly looked into, 

 but too minute investigations might be injurious to the 

 simple views I have taken. 



Mode of appraising the Price of Artificial Manures. 



For this purpose the following valuation may be 

 useful. The price affixed is that of 1 lb. of each 

 substance named. 



s. d. 



1. Nitrogen, as ammonia (or nitric acid), 1 3 



2. Nitrogen, which has undergone no alter- 



ation by putrefaction or decay, . . 11 



3. Organic or humus-forming substances, OJ 



4. Salts of potash, 2 



Or potash separately, .... 3 



5. Salts of soda, IJ 



6. Phosphate of lime, or phosphoric acid 



earths, Ij 



Or phosphoric acid, separately, . . 2 



7. Gypsum, i 



8. Lime, |- 



If a farmer desires that a manure met with in 

 commerce should undergo examination, he will act 

 wisely in proposing to the chemist who is to insti- 

 tute the analysis, the following distinct questions : 

 1st. What quantity does it contain in 100 parts of 



