PROCEEDIXGS OF TEE PoLYTECHXlC ASSOCIATIOX. 1027 



This method is one of the most interesting, from a scientific point 

 of view, as two kinds of oxygen, ozone and antozone, are libera- 

 ted. According to Schoenbem, we . obtain ozone from the chromic 

 acid and antozone from the binoxyd of Iiydrogen, and these two 

 conditions of oxygen nnite to produce the ordinary gas. 



13. By boiling a solution of bleaching powders in a glass flask, 

 with a few drops of nitrate of cobalt, oxygen gas is copiously evolved. 

 The cobalt salt is not consumed, as it acts by its presence. 



This method works very well in a small way, as we have had 

 occasion to prove in our laboratory. It is, however, more inconven- 

 ient than the employment of chlorate of potash. 



14. Sulphate of zinc, at a high heat, yields oxyd of zinc, sulphur- 

 ous acid and oxygen. In establishments where the zinc salt is pro- 

 duced from galvanic batteries, it is sometimes advantageously 

 employed in the preparation of oxygen. 



15. The permanganate of potash, when subjected to heat, yields 

 very pure oxygen. This method could be employed in medical 

 cases, but would be too expensive on a larger scale. 



16. Schoenbein once exhibited to us an experiment in his labora- 

 tory which we have never seen attempted elsewhere. It may sug- 

 gest a method for the preparation of oxygen on a large scale. When 

 spongy ruthenium is plunged into chlorine water, oxygen gas is given 

 off in large quantities, and this will continue as long as there is any 

 chlorine present in the water. The hydrogen of the water goes to 

 the chlorine forming hydrochloric acid, and the oxygen is set free. 



Schoenbein was of the opinion that by passing a continuous 

 stream of chlorine gas into a yessel containing water and spongy 

 ruthenium, oxygen gas would be given off in great quantity. As 

 the result of hydrochloric acid could be used for the preparation of 

 chlorine gas, and as the spongy ruthenium is not all affected, the 

 expense of this method resolves itself into the cost of the chlorine 

 and the original outline for the spongy ruthenium. We can hardly 

 hope to see this proof employed on a large scale ; but in a small way 

 it is certainly very interesting and instructive. 



17. It has long been considered desirable to obtain oxygen either 

 from the atmosphere or from water. The water methods have not 

 proved practicable, and we will give three ways where the oxygen is 

 derived from the air. 



The French chemist Boussingault proposes to heat gently the 

 oxygen of barium (baryta) in a current of air, by which it would be 



