Chemical and Physical Papers. 



47 



boat and the spirals of oxidized copper is determined by the nature 

 of the substance in the boat. 



The tube can be supported by clamps, or, what is still better, a 

 sheet-iron trough lined with asbestos paper, as described in part I 

 of this paper. The whole apparatus can be mounted on sheet-iron 

 supports. The following diagrams represent the relationship of 

 the parts: 



d e f 



III. walker's method. 



The third method employed in conducting this comparative test 

 was what is known as Walker's method, the apparatus having been 

 designed and used under the directions of Prof. James Walker, of 

 the University College of Dundee.^ 



The most significant feature of this method is that the size of 

 the furnace is greatly reduced and simplified. The apparatus is a 

 modification of the apparatus used in the Dennstedt process, the 

 only essential difference being that the combustion tube is much 

 smaller and copper oxide is used instead of platinized quartz. The 

 apparatus as used in the experiment herein described consisted of 

 a combustion tube 70 cm. long and 9 mm. inside diameter. 



The furnace is heated quickly and cools quickly; this means a 

 great saving of time. The heat applied is not great enough to 

 bend the tube. About the only disadvantage found was that it 

 was deemed necessary by the authors to remove all the copper 

 oxide every time a combustion was made. But even this is not 

 necessary; one need remove only suflacient copper oxide to mix 

 with the substance, and to rinse the tube. The introduction of 

 the sample by means of a porcelain boat is, however, much simpler 

 still. This simple furnace is perfectly satisfactory for all purposes 

 of ordinary combustion. 



The substances used in conducting the experiments were acetan- 

 ilide and aniline. 



1. Compare Proceed. Royal Soc. of Edinburer. vol. 28, p. 708. 



