MANUAL FOR SUGAR GROWERS. 



73 



small quantities at a time, to obtain the best results ; 

 about one liundreclweight per acre being a conve- 

 nient quantity. 



Ferrous sulphate, or sulphate of iron, is attracting 

 some attention as a manure : the author has several 

 trial plots laid down this 1891-92 season. In one 

 experiment last season there was a most marked dif- 

 ference in the appearance of the canes manured with 

 this substance ; throughout the whole period of 

 growth they were greener and taller than the ad- 

 joining canes — part of the same field — not manured 

 with sulphate of iron, but otherwise similarly treated. 

 Unfortunately, accurate quantitative results were not 

 obtainable, but, as far as could be ascertained by 

 weighing the canes from one-fifth of an acre from 

 each plot, there was an increase of six per cent, in 

 the weight of the canes in favor of the sulphate of 

 iron, and this on second ratoons in a very dry season. 

 The individual canes, too, from the sulphate of iron 

 plot were finer looking. The juice from the canes 

 manured with sulphate of iron and those not so 

 treated was carefully analysed to discover if the iron 

 exerted any influence on the juice ; no difference could 

 be detected. The figures obtained are given below. 



Juice from canes with sulphate iron 



Juice from canes without sulphate iron. 



Glucose 

 ratio. 



1.85 

 1.83 



These results agree within the limits of analytical 

 error. 



