112 . THE CONNECTICUT AGRICULTURAL 



On the Deteemixation of Nitrogen by Combustion witb 



Calcium Hydroxide. 



In a paper by the Director, published in the American Chemist 

 for 1873 (vol. III, p. 161), it was shown that the mixture of 

 sodium hydroxide and calcium hydroxide or oxide, proposed by 

 Will and Varrentrapp as a reagent for converting organic nitro- 

 gen into ammonia for the purposes of analysis may be advan- 

 tageously replaced by a more easily prepared mixture of sodium 

 carbonate and calcium hydroxide. When preparing that paper 

 some combustions were made with simple calcium hydroxide and 

 in case of uric acid for instance, the amount of nitrogen obtained 

 fell short of the theoretical quantity by less than one per cent. 

 As no entirely satisfactory results were then reached by burning 

 with simple slaked lime, it was concluded that the presence 

 of an alkali hydroxide, which it was thought might be formed in 

 small quantity in the process of combustion, was necessary to the 

 complete conversion of the nitrogen into ammonia. Further 

 trials were then contemplated but not until recently has the 

 opportunity offered to carry them out. A series of analyses 

 whose results are here given, demonstrate that this further sim- 

 plification of the Will' and Varrentrapp method applies to all 

 those classes of substances, which are ordinarily encountered in 

 technical work. 



The calcium hydroxide was prepared from a good quality of 

 quick lime by slaking with water in but slight excess, drying 

 off any surplus of water at a modei-ate heat, rubbing gently in a 

 mortar, passing through a sieve of -^^ inch holes and bottling in 

 well-closed " fruit jars." 



The tubes were filled and the combustions were made in the 

 way indicated in the Report of this Station for 1878, page 116. 

 The points to be observed are chiefly these. For the burning of 

 0.5 gram of substances containing 8 per cent, of nitrogen or less, 

 a tube of 14 inches is long enough. For dried blood or albu- 

 minoids containing from 12 to 17 per cent, of nitrogen a tube 2-4 

 inches longer is desirable. 



The mixture of substance and slaked lime must not quite half 

 fill the tube in length-wise direction. The long anterior layer of 

 slaked lime must be brought to a full red heat before heating the 

 mixture, and must be so kept throitghout the combustion. 



