412 



RECENT PROGRESS IN PHYSICS. 



ter tube was immersed in a wider vessel filled with water. Sometimes 

 the water was covered with a layer of oil one inch in depth. 



Fig. 51. 



Fig. 52. 



When the gases had to he confined over mercury, or when a longer 

 continuation of the ignition was necessary, the apparatus of fig. 52 

 was used. He:e the eudiometer tube is bent, and its closed end, con- 

 taining the platinum wire, immersed in a vessel filled with water or 

 oil ; the open end dipping into another vessel containing the water or 

 mercury, used for confining the gases. With this apparatus the 

 following results were obtained : 



Nitric oxide, over distilled water, contracted in varying proportions 

 to the heat. (The volume, of course, was not measured before the 

 apparatus had entirely cooled.) In the best experiments the contrac- 

 tion amounted to one-third of the original volume. The remaining 

 gas was nitrogen, and nitric acid was found dissolved in the water. 



Nitrous oxide was decomposed into nitrogen and oxygen ; the 

 volume increased by 0.35 of the original. The full equivalent pro- 

 portion or 0.5 could not be obtained. 



Carbonic acid did not show any perceptible change. 



Ammonia increased to double its original volume ; the gas could no 

 longer be absorbed by water, and consisted of 3 vol. of hydrogen and 

 1 vol. of nitrogen. 



Olejiant gas contracted a little, and deposited carbon. The re- 

 mainder was hydrogen and olefiant gas ; the greater the heat the 

 more hydrogen was formed. 



Nitrogen remained unchanged. 



Oxygen contracted but very little, about one-fiftieth of its volume ; 

 it might, perhaps, have contained a minute quantity of hydrogen. 



Chlorine over water gave white fumes, and a grayish-yellow insolu- 

 ble powder collected on the sides of the tube, near the platinum wire; 

 this was afterwards found to be chloride of platinum. The greatest 

 part of the chlorine combined with the hydrogen of the aqueous vapor, 

 and the muriatic acid formed was absorbed by the water. When the 

 experiment was finished the volume of gas was reduced to about one- 

 half, and the remainder was oxygen. 



With bromine and iodide of chlorine oxygen was evolved, (how the 

 experiments with these bodies were performed I could not perfectly 



