316 EDWARDS: AMMONIA IN ILLUMINATING GAS 



CHEMISTRY. — The iodine number of linseed arid peproleum oils.^ 

 W. H. Smith and J. B. Tuttle, Bureau of Standards. 

 Communicated by G. K. Burgess. 



The iodine number of linseed and petroleum oils was determined 

 according to the Hanus method. Each of the three factors, 

 weight of sample, time of absorption, and amount of Hanus solu- 

 tion, was studied for a series of burnt linseed oils and petroleum 

 oils. ■ Variations of weight of the raw linseed oil shows that a 

 constant volume is obtained for weights of the oil up to 0.25 gram. 

 Beyond this value the iodine number decreases with increasing 

 weight. For burnt linseed oils the range of weight over which 

 the iodine value is constant decreases with increased burning of 

 the oil. Petroleum oils on the contrary approach a constant 

 value when 0.6 gram or more of the sample is taken. Varying 

 the time of absorption from five to sixty minutes shows that the 

 reaction approaches a maximum in about ten minutes. There- 

 after absorption is slow, and a few minutes one way or another 

 has little effect on the value obtained. When the amount of 

 Hanus solution is varied from 20 to 75 cc the results indicate that 

 the oil with the highest iodine number does not require the greatest 

 excess of iodine to reach maximum absorption value. The effect 

 of temperature on the value obtained is more marked for burnt 

 linseed oils than for boiled or raw oils. The results as a whole 

 indicate that concordance is obtained only when a prescribed 

 procedure is followed with exactness. To obtain comparable re- 

 sults a standard procedure should be followed in which the limits 

 are strictly defined. This is particularly true of burnt linseed oils. 



CHEMICAL TECHNOLOGY.— T/ie determination of ammonia 

 in illu7ninating gas.- J. D. Edwards, Bureau of Standards. 

 Communicated by G. K. Burgess. 



The method generally used for the determination of ammonia 

 in purified illuminating gas depends upon the absorption of the 

 ammonia in a standard acid solution, the amount of ammonia ab- 

 sorbed from a measured volume of gas being determined either by 



iTo appear in full as Bureau of Standards Technologic Paper No. 37. 

 2 To appear in full as Bureau of Standards Technologic Paper No. 34 (in 

 press)." 



