174 AGRICULTURAL EXPERBIENT STATION. [Jan. 



Marl. 



[I. and II. Sent on from Baltimore, Md. III. Sent on from South Framingham, 



Mass.] 



I. and II. Are samples of "green marl;" they belong 

 to a valuable class of marls. 



III. This material, sent on "as a sample of marl," is 

 essentially a carbonate of lime of fine aggregation and of a 

 soft texture ; and for this reason it deserves recommenda- 

 tion for agricultural purposes, wherever an addition of lime 

 will benefit the soil in the interest of the crops raised upon it. 



Peruvian Guano. 



[Sent on from Taunton, Mass.] 



jNloisturo at 100° C, 



Total phosphoric acid, .... 



Soluble phosphoric acid (8 cents per pound), 

 Reverted phosphoric acid (7^ cents per pound) 

 Insoluble phosphoric acid (3 cents jDer jDound) , 

 Potassium oxide (4^ cents per pound), 



Total niti'ogen, 



Actual ammonia (17i cents per pound). 

 Organic nitrogen {\1\ cents per pound), . 

 Niti'ogen as niti-ic acid (16 cents per i^ound). 

 Insoluble matter, 



Valuation per 2,000 pounds, 



Per cent. 



12.17 



18.45 

 1.54 

 5.92 



10.99 

 3.46 

 6.13 

 3.94 

 0.86 

 0.33 



13.64 



$38 74 



