44 Kansas Academy of Science. 



organic analysis and devised methods by which these principles 

 could be used in quantitative determinations. 



But little was done after the death of Lavoisier until 1806, when 

 Saussure, Th^nard and Berthollet made an attempt at organic 

 analysis. Their method was essentially one of mixing the sub- 

 stances to be analyzed, in the form of a vapor, with oxygen and 

 exploding the mixture or decomposing the substance at a high 

 temperature. By this means they succeeded in converting the 

 carbon and hydrogen into permanent gaseous compounds. With 

 many substances they obtained good results. 



The next modification of the process was made by Gay-Lussac 

 and Thenard. They continued the process of Lavoisier, but used 

 potassium chlorate as an oxidizing agent. A definite quantity of 

 the substance to be analyzed was mixed with potassium chlorate^ 

 and the mixture heated. They obtained some good results for car- 

 bon and hydrogen. In the nitrogen determination they used cop- 

 per oxide. The results obtained were good with a small number 

 of substances. 



Berzelius continued the work, using Lavoisier's plan. He used 

 potassium chlorate as an oxidizing agent. The activity of the 

 action was modified by the addition of sodium chloride. 



The work of Liebig (1823-1830) is considered to be the most 

 important contribution from the time of Lavoisier to the present. 

 Liebig succeeded in perfecting the first process that would produce 

 satisfactory results- Liebig used a hard glass tube about 18 inches 

 long and 0.5 inch in diameter. The tube was closed at one end, 

 the closed end being drawn out to a sharp tip. The tube was 

 charged for a few inches with granular copper oxide. The weighed 

 substance was added, mixed with fine copper oxide. The tube was 

 then filled with copper oxide. Calcium chloride was used to ab- 

 sorb the water, and potassium hydroxide to absorb the carbon 

 dioxide. The tube was heated in a charcoal furnace. To remove 

 all the gas from the tube an aspirator was attached to the potassium 

 hydroxide bulbs, the tip of the closed end of the combustion tube 

 was broken ofip and dry air allowed to enter. Liebig succeeded in 

 making satisfactory nitrogen determinations. 



Liebig's process, with a few modifications, is the one in general 

 use at the present time. The substance can be completely burned, 

 and if sufficient care is exercised satisfactory results are obtained. 



The furnace used at present is provided with a tube open at both 

 ends. Through the rear end dry oxygen is admitted. At the op- 

 posite end the absorption apparatus is attached. A tile furnace is 

 used, and heat is supplied by means of gas burners. 



