34 METHODS OF ANALYSIS. 



10. Lime-Sulphur Dips and Lime-Sulphur-Salt Mixture. 

 (a) TOTAL SULPHUR^ AVEBY METHOD. PROVISIONAL. 



(1) SOLUTIONS REQUIRED. 



(a) Alkali solution. Use a saturated potassium hydroxid solution or a solu- 

 tion of sodium hydroxid containing 100 grams to 100 cc of water. 



(6) Barium chlorid. A 10 per cent solution. 



(c) Hydrogen peroxid. An approximately 3 per cent solution, free from 

 sulphates. If the solution contains sulphates add freshly precipitated barium 

 carbonate and shake occasionally for several hours, then filter and use the 

 clear solution. 



(2) DETERMINATION. 



Measure 10 cc of the clear sample in a 100 cc measuring flask and fill to the 

 mark. Analyze 10 cc aliquots of this solution. Treat with 3 cc of the caustic 

 potash or soda solution, following by 50 cc of hydrogen peroxid free from 

 sulphates. Heat on the steam bath for one-half hour exactly and then acidify 

 with hydrochloric acid, precipitate with barium chlorid in the usual way in 

 boiling solution, and finally weigh as barium sulphate. 



11. Lead Ar senate. 



See Appendix, page 239, for provisional methods adopted by the association 

 in 1907. 



a TJ. S. Dept. Agr., Bureau of Chemistry, Bui. 90, p. 105. 



