540 



Felspathic Rocks as Fertilisers. 



[dec, 



seen on the green, and two whole seasons have passed with no 

 trace whatever of anything in the shape of a fairy ring. Owing 

 to the large amount of sulphate of iron used, over a ton to the 

 acre, it was deemed advisable to give a heavy dressing of lime 

 tojreduce any remaining in the ground to a harmless state. 

 A week after the last application, quick-lime, freshly slaked 

 to a fine powder, was evenly spread over the surface at the 

 rate of i ton per acre. 



The success of these operations was so pronounced that 

 other greens similarly affected are being treated this autumn. 

 A few precautions should be taken by those who try this 

 method. Chief amongst them is the necessity for keeping the 

 ground moist, while on no account must the dressing of lime 

 a week after the last treatment be omitted. The area to be 

 treated is better left without rolling, and it is well to cut the 

 grass only once a week during the work, say two days before 

 each application. Though four doses were given, it is possible 

 that three would prove sufficient, but less than that might 

 leave some spawn uninjured in the soil to form the centre of 

 another outbreak. The autumn — when the fungus is actively 

 growing — is the proper time for the work ; in the height of 

 summer, or in the depth of winter, the prospects of success are 

 not so good, while the risk of injury to the grass is greater. 



In view of the need for potash as an agricultural fertiliser 

 and of the fact that the potash deposits in Germany represent 



the only known source of raw potash, 

 The Use of Felspathis interest has been revived in the United 

 Rocks as Fertilisers. States in the use of ground felspar as a 



manure, a subject which has attracted 

 no attention in this country since Dr. Aitken's experiments 

 were published twenty years ago in the Transactions of the 

 Highland and Agricultural Society. Felspar is a mineral in 

 which alumina and other bases, such as potash, soda, lime, 

 are combined with silica. Orthoclase felspar, a silicate of 

 alumina and potash, should contain nearly 17 per cent, of 

 potash, but in many of the felspars the potash is to a greater 

 or less extent replaced by soda or lime or both. Granite con- 

 sists of felspar, quartz and mica in varying proportions ; and 

 ordinary granite may contain from 3 to 5 per cent, of potash. 



