COMPOSITION OF SOME LIME-SULPHUR SPRAYS. 243 
The boiling was done ina flask under a reflex condenser, 
pure lime and pure sulphur were used throughout. The 
_~methods of analysis used are those published in the Journal 
of Agricultural Science.* 
Mayers method,” Podreschetnikofi’s method,* and that 
of Dusserre and Vuilleumier* were tried and abandoned 
as unsatisfactory. The methods described by James HE. 
Harris® were adopted with slight modifications and gave 
excellent results. In using sodium peroxide as an oxidising 
agent to convert sulphides of alkaline earths into sulphates, 
the method as recommended by Harris which is apparently 
Modrakowski’s® method is as follows :— 
**10 cc. of diluted solution is placed in a tall beaker, 
covered with a watch glass and 5 or 6 grams sodium per- 
oxide added. After standing a few minutes hydrochloric 
acid is added with stirring until the solution clears uy, 
. « . . after ooiling a few minutes to drive off dissolved 
gases the sulphur may be precipitated as barium sulphate.”’ 
I have followed this method and have failed to obtain 
concordant duplicates. 
The reason I find is due to the presence of higher oxidised 
products—chlorates, for such a solution discharges the 
colour from methyl-orange and from indigo. This fact has 
been noted by Pringsheim.’ 
* Journal Agricultural Science, Vol. v1, pt. ii, May 1914, p. 194. 
2 E. Dhvique-Mayer, Rev. génér. Chim. pure appl. 1908, p. 273 — 274. 
Analyst xxxitl, p. 484. 
3 E. Podreschetnikoff, Zeit. Farben Ind. 1907, p.6--388. Analyst xxxiII, 
p. 14t. 
* E. Dusserre and V. Vuilleumier, Chem. Zeit., 1909, p. 33-1129. 
Analyst xxxIv, p. 545. 
° James E. Harris, Technical Bulletin No.6, Michigan Agricultural 
College, 1911. 
® G. Modrakowski, Zeit. physiol. Chem. 1903, xxxvitl, p. 562. Analyst 
XXVIII, p. 321. 
7 H. H. Pringsheim, Berichte 1903, xxx, p. 4244-4246. Analyst 
Rix, p. 97. 
