Basic Slag. 



79 



that not only has the total percentage of pho.sphoric oxide in slag 

 diminished, but even of that reduced total a much smaller propor- 

 fion than before is soluble in citric acid. 



Although, therefore, I think that the regulations need umeiid- 

 ment*, it will never do to relax them to an extent that will permit 

 of the unrestricted sale in this country of material which may later 

 oil be shown to possess but the scantiest agricultural value. 



The Temptation oi- AD^rixiiVG. 



There is another consequence of the altered quality of basic 

 slags to which T wish to draw attention. The temptation to admix 

 other phosphates has obviously become greater than it used to be, 

 and quite recently the term " slag phosphate " has been a implied in 

 l^higland to a mixture of basic slag and mineral phosphate which has 

 appeared on ihe British market. Dr. Russell has issued a warning 

 to farmers to be careful to realize exactly what these words stand for 

 when they are used. 



Mixtures such as these have not yet, as far as I know, made 

 their appearance in South Africa, but doubtless they will not be 

 long in coming, and in the meanwhile I may also draw attention to 

 a note published in the New Zealand Jourtial of Agriculture about 

 three months ago by the New Zealand Agricultural Chemist to the 

 effect that phosphate rock from Nauro and Ocean Islands has been 

 sold to a Welsh basic slag company for the purpose of grading up 

 their slag, and that the British Ministry of Agriculture has recom- 

 mended farmers to try this mixture of slag and phosphate rock on 

 their grass lands, and to lay thereby a good foundation for arable 

 land. Regarding this mixture, too. experiments are in progress, 

 both in Great Britain and in New Zealand, and for the present it 

 only lies with us to dih'erentiate between it and true basic slag'. 



Outbreaks of Animal Diseases : May, 1922. 



* The Regulations were amended by Govemment Notice No. 963 of the 14th June, 1922, 

 which provides that the minimum content in basic slag of phosphoric oxide soluble in citri<- 

 acid shall be 10 per cent, instead of 12 per cent. 



