IOWA ACADEMY OF SCIENCES. 71 



A NEW DISTILLING FLASK FOR USE IN THE KJELDAHL PROCESS. 



By G. E. Patrick and D. B. Bisbee. 



The only serious drawback to the Kjeklahl method of nitrogen determin- 

 ation is the breakage of distilling flasks, and in laboratories where many 

 determinations of albuminoid nitrogen are made by the Stutzer process 

 this breakage is often a matter of much annoyance and considerable ex- 

 pense, since only the best quality of flasks will long stand the requirements 

 of the process. 



Some mouths ago the breakage in a certain lot of flasks purchased for 

 this laboratory having become unendurable, the writers hit upon the idea of 

 distilling from copper flasks; and upon trial, the results have been so satis- 

 factory that we can with confidence recommend the plan to other chemists. 

 The copper flasks used were the ordinary one pint oxygen retorts, minus 

 caps, delivery tubes and clamps. 



At first, trials were made by distilling ammonia from a solution of pure 

 ammonium chloride and NaOH, to assure ourselves that no ammonia was 

 retained by the copper. These results were made comparative by distilling 

 from both glass and copper flasks. Exactly 10 c.c. of an ammonium chlor- 

 ide solution of known strength were used in all following tests. The results, 

 after deducting for ei-ror found by blank experiment, wei*e as follows: 



IN GLASS IN COPPER 

 FLASKS. FLASKS. 



No. of C.C. of decinormal acid neutralized 14.4 14.25 



14.23 14.23 



14.2 14.30 



14.28 14.25 



14.3 14.25 



14.15 14.30 



-Mean of six 14.26 , 14.26 



Next a salt of mercuiy was added to the ammonium salt in the flask, and 

 K2 S sufficient to precipitate the mercury was added before liberating the 

 ammonia and distilling. The following were the results after deducting for 

 the error in the blank: 



IN COPPER 

 FLASKS. 



No. of C.C. decinormal acid neutralized 14.13 



14.25 



14.25 



14.2 



14.25 



14.25 



.Meanofsi.\ 14.22 



