113 



V. Action of citric acid on slag. 



Amount of acid neutralized in times ranging from one-half to live 

 hours, at 25° C and at ti5° C. Amount of phosphoric acid remain- 

 ing in solution at the end of these periods. The phosphoric acid 

 in solution decreases with a rise in temperature and with an increase 

 in time. 

 VI. Comparison of the U. S. official method with the method proposed by 

 Dr. Paul Wagner, including special molybdate and magnesia solu- 

 tions. 

 The paper will be found in complete form in Bui. 49, Chem. Div. U. S. Dept. 

 Agr., p. 68-72. 



Laboratorj- State Chemist of Iiuliana. Punlue Univ., Nov., 1896. 



The Character of the Volatile Matter Lost by Bituminous Coals at 

 1(10= C. By W. E. Burk. 



The conditions accompanying the common method of determining moisture 

 in coal suggested a study of the nature and amount of volatile matter given off at 

 the temperature of determination. 



The work was done on two classes of Indiana coals, one high in moisture, the 

 other considerably lower, the operation consisting in passing the volatile products 

 from the coal heated approximately to 100° C, together with a current of dry air 

 over copper oxide in a combustion furnace, absorbing the moisture coming over 

 with calcium chloride, and carbon dioxide arising from combustion of any vola-- 

 tile hydrocarbons in a caustic potash solution. 



A hard glass combustion tube was used, which extended some 20 c. m. from 

 the forward end of the furnace. This portion of the tube was jacketed with a 

 glass sleeve with rubber plugs, and arranged with entrance and exit openings 

 through which a continuous current of steam was passed. By this means a tem- 

 perature approximating 100° C was maintained through the forward part of the 

 tube in which a weighed quantity of powdered coal was placed in an aluminum 

 boat. A slow current of dry air was passed, and the heating of coal and com- 

 bustion of volatile products maintained for one hour. The boat was then removed 

 and the absorption bulbs weighed, after which they were attached again and the 

 tube heated for a further twenty to thirty minutes. The boat containing coal was 

 weighed in a glass enclosing tube, and after the operation was allowed to cool in 



