WoLTERECK — Production of Ammonia from Atmospheric Nitrogen. 55 



water, and a f -inch iron barrel was substituted therefor. It was found, after 

 many experiments, that the presence of an increasing quantity of water- 

 vapour was an advantage, and the gases were passed through distilled water 

 at about 80° 0. before entering the tube. 



I have since been able to repeat and confirm these experiments with a 

 quartz tube. 



From the experiments carried out the following are typical — A f -inch 

 iron barrel filled with crystalline iron oxide was heated to a dull red heat ; 

 the quantity of gases passed through was — air 1'81 cubic feet, and illuminat- 

 ing gas 0'92 cubic feet (proportion 2:1); the total ammonia produced was 

 544 mg. 



Oxidized wire was next substituted for iron oxide and the quantity of 

 illuminating gas reduced step by step until 5-2 cubic feet of air and 0-066 

 (proportion 78:1) of illuminating gas produced 112'2mg. ammonia. This 

 led to experiments in which illuminating gas or free hydrogen was omitted 

 altogether, an experiment being made under the following conditions : — 



A l|-inch iron barrel with a T piece fitted into it for insertion of a pyro- 

 meter, so that the exact temperature could be determined, was filled with 

 freshly reduced iron wire gauze ; and over this air, carefully freed from 

 impurities and mixed with steam, was passed. 



A more exact description of the apparatus used in the following quanti- 

 tative experiments described will show that no precaution was omitted 

 to obtain indisputable results. 



The genera] arrangement of the apparatus in all the quantitative experi- 

 ments referred to was as follows : — 



The air was taten through an experimental wet meter (either pressure or 

 suction may be used) giving readings in iV cubic foot per revolution, and 

 having four dials to allow readings to be taken up to 1000 cubic feet to allow 

 for continuous work. The water filling the meter was carefully tested for 

 ammonia. The gases from the meter passed a precision-valve, by means of 

 which the flow of the same could be exactly regulated to prevent any change 

 in the amount of air passing the apparatus in any given time after having 

 once been regulated. 



The air passed next through a wash-bottle containing concentrated 

 sulphuric acid which had been proved to be free from any nitrogen compounds 

 by careful tests. From this wash-bottle the air passed through a flask con- 

 taining a measured quantity of distilled water, free from nitrogen compounds, 

 kept in a continuous level water-bath at a temperature of 80°0. From this 

 flask, the air, now saturated with water-vapour, passed into the iron barrel 

 placed in a combustion furnace, and containing the rolls of iron gauze or other 



