UNITED STATES DEPARTMENT OF AGRICULTURE 



Contribution from the Bureau of Animal Industry 

 A. D. MELVIN, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



December 14, 1916 



THE CHEMICAL COMPOSITION OF LIME-SULPHUR 



ANIMAL DIPS. 



By Robert M. Chapin, Senior Biochemist, Biochemic Division. 



CONTENTS. 



Page. 



Experimental materials and methods 1 



Effect of storage 2 



Effect of lime added after dilution 3 



Effect of varying lime-sulphur ratio 4 



Effect of varying period of boiling 5 



.iilect of varying concentration 6 



Occurrence and relations of calcium sulphite . 7 



Page. 



Ratio of polysulphid to thiosulphate 8 



Lower polysulphids; effect of excess of lime ... 9 



Higher polysulphids ; effect of oxidation 11 



Conclusions 12 



Practical applications 15 



References to literature 16 



The literature on the subject of lime-sulphur solutions is already 

 voluminous. But even the ablest investigators have been handicapped 

 by limitations in their methods of analysis, while some of the pub- 

 lished work, especially in recent years, has been of such a character 

 as to bring the whole matter into a state of confusion. Inasmuch as 

 the writer has been able to develop some new methods of analysis 1 ' 2 * 

 which appear in several ways superior to former ones, it has been a 

 logical step to utilize these new methods in a general study of the 

 composition of lime-sulphur solutions. The information so obtained 

 appears to determine decisively some facts which previously could 

 be only a matter of conjecture or at least only qualitatively studied, 

 and others which have been the subject of dispute, although it very 

 likely brings out little radically new. Lime-sulphur solutions are 

 of considerable practical importance and precise information re- 

 garding them is of distinct value. 



EXPERIMENTAL MATERIALS AND METHODS. 



The general plan of investigation was necessarily simple, merely 

 involving the preparation of solutions according to different formulas 

 and under different conditions, with subsequent analyses and com- 



a The figures refer to the list of references at end of bulletin. 

 59847° — 16 



