34 



to me in regard to it. Some of the trees sprayed by this solution 

 would be very much whitened, as if whitewashed, whereas other trees 

 sprayed from the same tank as these would be scarcely discolored by 

 the wash. It is, of course, the slaked lime added to the solution that 

 causes it to give the trees the appearance of having been whitewashed, 

 since neither the salt nor the sulphur discolor the tree to any appreci- 

 able extent, and the same is true of the bisulphite of lime, which is pro- 

 duced by boiling the quicklime and sulphur together. 



The cost of 100 gallons of this wash according to prices furnished me 

 by Howell & Craig, wholesale grocers, of this city, for the sulphur and 

 salt, and by the Southern California Lumber Company, also of this 

 city, for the lime, is as follows, the materials being purchased in large 

 quantities : 



Sulphur, 33 poun ds, at 2i cents per pound $0. 70 



Lime, 42 pounds, at § of a cent per pound 33 



Salt, 25 pounds, at - 2 s o of a cent per pound 11 



Total $1.14 



The salt quoted above isapoor grade, such as is used for salting hides, 

 and the price quoted is by the ton ; the sulphur is in sacks, and the 

 lime in barrels containing about 220 pounds each. 



Of the two washes above described — the resin, caustic soda, and fish 

 oil, and the lime, salt, and sulphur washes — the one containing resin is 

 greatly to be preferred. Kot only is this wash easier to prepare than 

 the other, but it is also much easier to apply it to the trees, since it is 

 perfectly soluble in water and therefore does not require to be stirred 

 while being sprayed upon the trees. For this reason more uniform re- 

 sults will be obtained by its use than would be obtained by using the 

 sulphur wash. Moreover, the resin wash, by being properly diluted, 

 can also be used in the summer season, and thus only one wash need be 

 used at any time of the year. In my own experiments better results 

 were obtained by the use of the resin wash than were produced by the 

 sulphur wash. The price per gallon of each of these washes is about 

 the same. The sulphur wash should never be used on trees in leaf nor 

 on those just starting to leaf out, and this is also true of the resin wash 

 when made according to the formula given in the preceding article. 



MISCELLANEOUS EXPERIMENTS. 



Corrosive sublimate (also known as mercuric chloride, HgCl 2 ). — 

 Some time ago one of the Horticultural Commissioners of San Ber- 

 nardino County remarked to me that he had used a simple solution of 

 corrosive sublimate for the purpose of destroying various kinds of scale 

 insects on nursery trees, and had obtained very good results by the 

 use of the same ; and it was also reported in some of the San Diego 

 papers that a gentleman liviug in that county had obtained better re- 

 sults by the use of a solution of the above kind than he had by using 

 auy other kind of insecticide for the destruction of the black scale. 



