157 



taken by a hydrometer, and the quantity required for 

 mixing with a given quantity of water ascertained. 

 As there is risk of mistakes when this is done by 

 labourers, it is safer to weigh out the same quantity of 

 lime and copper, and measure the water each time in 

 the proportions of 2 Ibs. sulphate of copper, 1 Ib. lime, 

 10 gallons of water, when little chance of mistake is 

 offered. 



Specific Gravity of Copper Solution. 



For the preparation of considerable quantities of the 

 mixture, the following plan, adopted for the Warminster 

 plots, will be found convenient, and considerable time 

 will be saved, but it is obvious that someone with 

 intelligence should be present, to see that the proper 

 quantities are secured. 



Some days before the mixture is required, a paraffin 

 cask, with the head taken out (or more than one, if the 

 acreage to be done is considerable ), should be placed 

 upon a stage and fitted with a wood top. A short 

 canvas bag is nailed to two strips of wood, so that it 

 may be supported with the bottom about half way 

 down the cask. The bag is to be filled with sulphate 

 of copper crystals. The cask is then filled with water, 

 and the suspended crystals will, in a few days, have 

 dissolved almost to saturation point. 



There is thus made a strong stock solution, which 

 can be diluted as and when required. 



A hydrometer should be provided for testing the 

 strength of the solution, and the following table will be 

 found useful as showing the strength, corresponding 



