180 DISEASES OF GLASSHOUSE PLANTS 
of lime, and 50 gallons of water are employed. This is 
called the 3—6—50 formula. 
For less delicate plants the 4—4—-50 formula, or 4 lb. 
copper sulphate, 4 lb. lime, and 50 gallons of water, 
may be used, while on occasions it may be necessary to 
employ the 5—5—50 formula. 
Burgundy Mixture 
This is a modification of Bordeaux Mixture and was 
devised for use where good freshly burnt lime is unobtain- 
able. In this mixture washing soda is used instead of 
lime. The normal mixture is prepared from 4 lb. copper 
sulphate, 5 lb. washing soda, and 40 gallons of water. 
In practice, the copper sulphate is dissolved in 5 gallons 
of water, which is then made up to 35 gallons. The 
washing soda is dissolved in 5 gallons of water, and when 
solution is complete is added to the 35 gallons copper 
sulphate solution, stirrmg thoroughly all the time. 
When prepared correctly the mixture is bright blue in 
colour, and the fine precipitate it contains remains in 
suspension for a considerable time. Jf the colour is 
greenish the mixture has not been correctly made, 
and if the precipitate settles rapidly it will not adhere 
to the foliage. It is important to procure pure 
materials, and both copper sulphate and washing soda 
should be fully 98 per cent purity. The mixture must 
be used fresh and certainly not more than ten hours 
after preparation. 
On most plants correctly made Burgundy Mixture 
has a greater tendency to cause scorch than correctly 
made Bordeaux Mixture. 
Just as Bordeaux Mixture containing an excess of 
lime is less likely to scorch foliage than the normal 
mixture, so the same effect is produced in Burgundy 
Mixture by an increase in the proportion of washing 
soda. In cases where normal Burgundy Mixture has 
caused scorch, the 4—6—40 mixture, in which the washing 
