660 EXPERIMENT STATION RECORD. 



f,'i'(>wlli of tlio new shoots. 1( can lie coiilrollcd. Iiowcvci'. by sjirMyini: r(>i;;ularly 

 witli arsenate of lead. 



Sliraying experiments, ,7. Tkoop aiul ('. <;. Woonmitv (hiiliiiiKi Kta. Ritt. 

 liid'.K I'l). .}3, J/'i). — One hnmlrefl and fifty-fonr 4 to r, year old lives which were 

 quite uniformly infested by San Jose scale wei(> siuayed on March 7 and 8, 

 four commercial products being used. *• Tarj^et l)ran(i. contiary lo the writer's 

 former experience with this remedy, made a stable I'mulsion with water imme- 

 diately upon mi.xiuff and proved very ellicient against the scale. Bogart's 

 sniiilinr compound did. not enuilsify satisfactorily and was very inefflcient as 

 a scale destroyer. The two brands of lime sulphur [(Jrasselli and Niagara] 

 liolii diluted easily, but were not quite equally effective." 



Spraying trees for tlie elm scale, S. B. Doten {Nevada 8ta. Circ. 6, pp. 6, 

 figft. 3). — This is a brief accoimt of the European elm scale and its control, a 

 more extensive account of which has been ])reviously nf)ted (E. S. R., 20, p. 

 655). 



Experiments show that it is readily destroyed through spraying with a mix- 

 ture of 20 lbs. of (]uicklinie, 15 lbs. of tiowers of suli)hur, and 50 gal. of water. 

 As the lime-sulphur mixture turns the paint of houses and fences black, it has 

 been found advisable to use kerosene enuilsions on cork elms close to dwelling 

 houses. 



Spraying, L. R. Taft {Michigan Sta. Rpt. 1909, pp. 150, 151).— A brief 

 account of the spraying work carried on during the year under report. 



A chemical study of the lime-sulphur wash, L. L. Van Slyke, C. C. 

 Hedges, and A. W. Roswortii {\<w York State Sta. Bui. 319, pp. 383--'i IS) .—The 

 work described in this bulletin was undertaken for the purposes of learning (1) 

 how the composition of the lime-sulphur wash is influenced by conditions of 

 preparation and (2) what is the composition of various connnercial prepara- 

 tions. Preparations were made containing 125 lbs. of sulphur and .52, 60, and 65 

 lbs., respectively, of pure lime. The general results are summarized as follows: 



" The specific gravity or density of the preparation and the amount of sulphur 

 and calcium in solution increased with the amount of lime used. 



" When the largest amount of lime was used, the compomid present was 

 mostly calcium tetrasulphid (CaS4) ; when the smallest amount of lime was 

 used, the mixture was more nearly pentasulphid (CaSr,). 



" In the undissolved portion or sediment, free sulphur was present in largest 

 amounts when the smallest amount of lime was used, and the amount decreased 

 when larger amounts of lime were used. Calcium sulphite Avas present in 

 smallest amounts when the least amount of lime was used." 



Different mixtures were also boiled 45, 60, and 90 minutes, with the following 

 results : 



"The largest amount of soluble sulphids was formed by boiling about 1 hour, 

 eRjtecially when the largest amount of lin)e was used. 



" In general, increased length of boiling decreases the amount of thiosulphate 

 and increases the amount of sulphite. 



" The amount of sediment increases with length of boiling, owing to increased 

 formation of calcium sulphite, etc. The amount of free sulphur in sediment 

 decreases with length of boiling." 



An examination was made of concentrated lionie-made mixtures and of 

 dilute mixtures prepared according to the fonnula 15 lbs. of snljihur and 20 

 lbs. of commercial lime, but the results were not as satisfactory as in case of 

 the other i)rei)arations already descrilxMl, probably because of the use of impui'e 

 lime. Iii the case of the 15:20 formula, the su]i>hid compounds of calcium 



