128 FIRESIDE SCIENCE. 



Here we have sixty-three per cent, of sand and 

 water, which are worthless materials, and which are 

 paid for at the rate of twenty or twenty-five dollars 

 a ton. 



Another specimen gave : 



Water 31.00 



Organic matter 35.00 



Phosphate of lime and various salts with sand . 34.00 



100.00 



This is better, but still one third of the whole 

 bulk is perfectly worthless. A popular " super- 

 phosphate," recently examined, gave twenty-two 

 per cent, of water, and only five and one half per 

 cent, of soluble phosphate. The fact that husband- 

 men are not generally competent to judge of the 

 value of compounds offered as fertilizers, has led to 

 placing on sale some of the most absurd substances 

 and mixtures which human ingenuity can discover 

 or devise. 



A heavy powder called the " Grafton Mineral 

 Fertilizer" has come into the market within a year 

 or two, and has secured a large sale at high prices. 

 What is the nature of this powder ? Let us judge 

 of it by the analysis which is presented in connec- 

 tion with its sale. Here it is : 



Silica 30.3 



Protoxide of iron . . . 6.27 



Lime 20.6 



Magnesia 11.17 



Carbonic acid .... 32.11 



