178 THE PRINCIPLES OF 



we got most definite results, which are embodied in the 

 report published by the North-Eastern Steel Company. 

 These experiments established in this country the effect of 

 basic cinder. Other experiments seem to have been going 

 on during the same season in Germany, and both in Germany 

 and in this country the effect of 'basic cinder as a fertilizer 

 has been thoroughly proved. It is a curious fact that basic 

 cinder should produce as great 'an effect as superphosphate, 

 which in many cases it does. Undissolved basic cinder pro- 

 duced pretty nearly as much effect as superphosphate with 

 ammonia salts, and a much better result than ground coprolites. 



The peculiarity of the basic cinder appears to be that it 

 contains a very large excess of lime in somewhat unstable 

 combination with phosphoric acid. To put the matter briefly, 

 we have in the case of monobasic phosphate one atom of 

 lime in combination with phosphoric acid. In reduced phos- 

 phate we have two atoms of lime united with one of 

 phosphoric acid, and in tricalcic phosphate, which is insoluble 

 phosphate, we have three atoms of lime. But at the high 

 temperature at which the basic cinder is formed, we get four 

 parts of lime united with the phosphoric acid. We have a 

 higher proportion of base, and a tetracalcic phosphate pro- 

 duced; but although it is true within limits that the larger 

 the proportion of lime the less soluble is the phosphate, yet 

 the excessive quantity of lime appears to introduce an element 

 of instability into the compound. It readily breaks down, 

 are this appears to be the reason why the basic cinder is 

 more efficacious as a manure than tricalcic phosphate, or 

 even than reduced phosphates. 



For the benefit of those who desire to test the comparative 

 value of artificial fertilizers by direct experiment, I will 

 indicate the general lines upon which"- these experiments 

 should be carried out. First I would select a uniform soil 

 in low rather than in high condition, for example, a soil that 



