SCIENCE AND INDUSTRY. 
a A TS RES TR ST a eT 
Alterations of Concentration of Dip.—Addition of both caustic soda 
and water are necessary as the dip is being used. To make these addi- 
tions without altering the concentration of the dip to a harmful extent. 
presents difficulty. In many cases too much caustic soda is added. 
Dilution by addition of cold water is then practicable, but this causes 
delay witil the dip again boils. The other alternative (continuation of 
work and over-cracking of berries) is too often accepted. The harm- 
ful effects of this has been referred to elsewhere. 
In the operation of dipping, the solution in the tank is affected as — 
follows :— 
1. There is concentration by evaporation of water. 
2. The volume of the solution is decreased by the removal of the 
quantity which wets the bunches. 
3. There is probably some slight neutralization of the caustic soda 
by fruit acids. 
The net result is a concentration in strength and a considerable 
diminution in volume. 
An attempt to meet the problem. was made as follows:—<A dip tank 
was filled to the 50-gallon mark with a solution of 1 lb. of caustic soda 
to 30 gallons of water. One hundred buckets of sultanas were dipped, 
and water was added to make up to the 50-gallon mark. A second 100 
buckets were dipped, and tank again made up to the 50-gallon mark _ ; 
with water. Three samples of the dip were taken. 
Sample 1. At commencement of operations. 
Sample 2. After addition of water, 100 buckets having been dipped. 
Sample 8. After second addition of water, 200 buckets having been 
dipped. 
Sultana grapes (Baumé 14.3) were used in this test, and all dipping 
was done at boiling point. 
The alkalinity of the y@¥ious samples was determined comparatively 
by titration with dilute H,SO,. 
Discussion of Results —Results indicate that 1 1b. of caustic soda 
was removed by 300 buckets (approximately). This work is at pre- 
sent incomplete. Application on a larger scale and subsequent testing 
under field conditions is necessary for confirmation. 
Relationship of Strength and Temperature of Dip to Colour of 
Dried Product.—The colour of dried fruit is dependent on a number of 
factors. Chief among these are— 
(a) Conditions of green fruit (vigour, stage of ripening, sue 
content, uniformity). 
(b) Weather during the drying period. 
(c) Distribution on drying rack. 
(d) Fungoid diseases due to attacks by parasitic Ree in fields 
and saprophytic fungi on rack. 
(e) Strength and temperature of dip. 
Discussion of Factors——On vineyards which have been under culti- 
vation for a number of years fruit frequently shows non-uniformity of 
ripening, low sugar content, and want of vigour (shown by early wilting. 
of berries). Obviously, on well-kept and well-manured vineyards, these 
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