21 
In limestone regions, or where the water is very hard, some of the 
soap will combine with the lime or magnesia in the water, and more or 
less of the oil will be freed, especially when the emulsion is diluted. 
Before use, such water should be broken with lye, or rain water 
should be employed. 
Kerosene emulsion (milk formula).—This formula is as follows: 
SEES SON tee a er ee ee el gallons__ 2 
AVILA AICS ULI yim 2 meres es SOR ED CEPA RS DEY Dy SE Se TS gallon-_ 1 
Heating is unnecessary in making the milk emulsion, which other- 
wise is churned as in the former case. The change from a watery 
liquid to a thick buttery consistency, much thicker than with the soap, 
takes place very suddenly after three to five minutes’ agitation. With 
sweet milk difficulty will frequently be experienced, and if the emul- 
sion does not result in five minutes, the addition of a little vinegar will 
induce prompt action. It is better to prepare the milk emulsion from 
time to time for immediate use, unless it can be stored in quantity in 
air-tight jars; otherwise it will ferment and spoil after a week or two. 
The distillate emulsion.—This wash was originated by Mr. F. Kahles, 
of Santa Barbara, Cal. It has been recommended by the California 
State board of horticulture and has found very general use in the 
citrus sections of the State. It is substantially an emulsion of crude 
petroleum, made in the same way as the kerosene emulsion described 
above, except that a greater amount of soap and only half as much oil 
proportionately is used. The lessened quantity of oil enables it to be 
made comparatively cheaply, and in spite of this reduction in the oil, 
the wash is, if anything, stronger than kerosene emulsion, judging 
from the experience of the writer with both these washes in southern 
California. 
It is termed distillate spray, because the oil used is a crude distil- 
late of the heavy California petroleum. The product used for pre- 
paring the emulsion should have a gravity of about 28° Baumé, and 
is the crude oil minus the lighter oil, or what distills over at a tem- 
perature between 250° and 350° C. In general characteristics it is 
very similar to lubricating oil. The emulsion, or, as it is generally 
known, “cream,” is prepared as follows: Five gallons of 28° gravity 
distillate; 5 gallons of water, boiling; 1 to 14 pounds of whale-oil 
soap. The soap is dissolved in hot water, the distillate added, and the 
whole thoroughly emulsified by means of a power pump until a rather 
heavy yellowish, creamy emulsion is produced. The product is very 
similar to, but rather darker in color than the ordinary kerosene 
emulsion. For use on citrus trees it is diluted with from 12 to 15 
parts of water, the stronger wash for the lemon and the weaker for 
the orange. The “ distillate cream ” is commonly prepared and sold 
by oil companies or individuals at from 10 to 12 cents a gallon, 
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