Chemical and Physical Papers. 45 



The following references were used in this historical sketch: 

 Quantitative Chemical Analysis, Julian, p. 295; Organischen 

 Chemie, Meyer and Jacobson, p. 19; Treatise on Chemistry, Ros- 

 coe and Schorlemmer, vol. 3, p. 40. 



For a long time there have been objections to the old form of 

 combustion furnace which is used in elementary organic analysis. 

 The furnace is expensive, it is heavy and requires a large amount 

 of table space. Much time is required in heating and cooling it. 

 If a small room is used the temperature soon becomes too high 

 for comfort. The quantity of gas used in heating the furnace and 

 the amount of oxygen consumed are both so large that methods 

 which will be less expensive than this one are very desirable. The 

 old form of furnace does not allow the flame to come near the tube. 

 The more recent methods aim to secure as near as possible direct 

 effects of the heat. Because of these facts simple and less expen- 

 sive apparatus have been designed. 



Three of the more recent and most inviting methods proposed 

 were tested by the writer and the results were compared with those 

 obtained by the older method. 



I. dennstedt's method. 



The first of the new methods employed was the one generally 

 known as Dennstedt's method, the apparatus having been designed 

 and carefully tested by Prof. Max Dennstedt, of Hamburg. Pro- 

 fessor Dennstedt's papers on the subject are to be found in Be- 

 nch te der deutschen Chemischen Gresellschaft, as follows: Vol. 30, 

 page 1590; vol. 38, page 3729; vol. 39, page 1623. 



A very carefully prepared paper has been published by Pro- 

 fessor Dennstedt under the title of "Anleitung zur Verinfachten 

 Elementaranalyse." 



The characteristic features of this method are that platinized 

 quartz is used in the combustion tube without copper oxide, and 

 that the nitrogen is determined by means of lead peroxide at the 

 same time that carbon and hydrogen are determined. 



This furnace has many desirable features. It costs but little, it 

 is easy to handle, is easily heated and cooled, and requires less gas 

 than the old form. Good results are said by some to be obtained 

 by experienced operators; by others the method is considered un- 

 satisfactory. I succeeded in getting a few good results for carbon 

 and hydrogen, but in spite of prolonged attempts and variation of 

 methods I did not succeed in getting a satiefactorj' result for nitro- 

 gen, as will be seen in examining the table. 



References on the above method are as follows: Anleitung zur 



