2-iO THUMAS-SLAG OR BASIC CINDER. 



In reviewing the ]uiblished records of the inanurial experi- 

 ments made with this substance, we may summarise theni in 

 the following manner : — 



The Thomas-slag possesses valuable manurial properties, due, 

 in the first place, to its containing phosphate of lime in a form 

 easily decomposable in the soil ; and, in the second place, to its 

 containing caustic lime. 



It is therefore an appropriate manure for turnips, leguminous 

 crops, clover grass, and pasture ; and secondly, for cereals, and it 

 is found to be well adapted for application to moorland, moss- 

 land, stiff clays, and wet meadow land. 



In order that it may be available as a manure at all, it must 

 be ground to an exceedingly fine powder. 



So far as is at present ascertained, the degree of fineness recpii- 

 site to ensure its success is that it should be able to pass through 

 a sieve of wire-cloth of at least 120 wires to the lineal inch. 



When groimd so finely that it is able to pass through wire- 

 cloth of 150 wires to the lineal inch, it is a very active manure, 

 capable of competing successfully with an equal weight of 

 superphosphate. 



When ground less finely its efficacy rapidly diminishes, so 

 that when only 80 per cent, of it passes through wire-cloth of 

 120 wires per lineal inch, it must be used in double quantity, so 

 as to compete with superphosphate. 



The amount of phosphate of lime in it varies from about 

 80 to 40 per cent. The finer ground part of the slag is richest 

 in phosphate. 



It should, therefore, be sold under a double guarantee — in the 

 first place, a guarantee of fineness ; and, in the next place, a 

 guarantee of percentage of phosphate. 



Seeing that it contains caustic lime, it should not be mixed with 

 sulphate of ammonia nor any manure containing ammonia salts. 



It has sometimes been mixed with superphosphate, but its 

 proper use is as a substitute for superphosphate rather than as 

 an adjunct to it. 



It should be well incorporated with the soil, and applied 

 early — perhaps in autumn. 



It has not been known to do any harm even Avhen applied in 

 large quantity, but from 4 to 10 cwt. per acre, according to 

 circumstances, is a favourable dose. 



It is not a complete manure, and therefore potash salts or 

 nitrogenous manures, or both, must usually be applied along 

 with it, just as in the case of superphosphate. 



There is an abundant supply of the substance, and it is a 

 valuable manure with a great future in store for it, if it can be 

 supplied at about thirty shillings per ton, and ground to an 

 exceedingly fine powder. 



