THE SOAP TREATMENT. 75 
whole mixture should be boiled for at least one hour, either in an iron 
kettle over a fire out of doors or in barrels by steam (see PL IX). 
Prolonged boiling increases the percentage of the higher sulphides, 
but the practical end is obtained with a boiling of the time indicated. 
In the process of making, the color changes from yellow to the clear 
brown of sulphide of lime, except for the excess of lime floating in it. 
After an hours boiling the full quantity of cold water can be added, 
and the mixture should then be promptly applied in order to get its 
full strength before the higher sulphides are lost by cooling and 
crystallizing out. In transferring to the spray tank it should be 
past thru an iron screen or strainer, and the tank itself should be pro- 
vided with an effective agitator. 
The wash is a winter application and can not be applied to trees in 
leaf. It may be applied at any time after the falling of foliage in 
early winter and prior to the swelling of the buds in spring. It will 
probably be necessary also to make this application every year, or at 
least as often as the San Jose scale develops in any numbers. The 
wash kills the San Jose scale not only by direct caustic action, but 
apparently also by reason of the coating on the trees, which remains 
in evidence until midsummer or later, and may kill or prevent the set- 
tling of any young scale insects which ma}' come from parents escaping 
the winter action. 
Two applications ma}' be given badly infested orchards — one in late 
fall, the other in late spring. Where but one application is given, the 
late spring just before the buds open is the best time. 
The wear on pumps and nozzles can be kept to a minimum by care- 
fully washing the apparatus promptly after .use. The Yerrnorel nozzle 
is the best one for the wash, and additional caps may be secured to 
replace worn ones. The use of an air or other gas pressure pump 
instead of the ordinary liquid pump will save the wear of the lime on 
the pump. In spraying with this wash clothing is ruined, and only 
the oldest garments should be worn. Care should be taken also to 
protect the eyes to avoid unnecessary inflammation. 
THE SOAP TREATMENT. 
Whale-oil or fish-oil soap, preferably made with potash lye, is dis- 
solved in water by boiling at the rate of 2 pounds of soap to the gallon 
of water. If applied hot and on a comparatively warm day in winter, 
it can be easily put on trees with an ordinary spray pump. On a very 
cold day, or with a cold solution, the mixture will clog the pump, and 
difficulty will be experienced in getting it on the trees. Trees should 
be thoroly coated with this soap wash. Pear trees and apple trees 
may be sprayed at any time during the winter. Peach trees and plum 
trees are best sprayed in the spring, shortly before the buds swell. 
