COMBINATION OF OXIMURIATIC GJLS AND OXIfiEN. ^(J^ 



combines witli hidrogen without any deposition of moisture: 

 it does not act on nitrous gas, or muriatic acid, or carbonic 

 oxide, or sulphureous gasses, when they have been carefully 

 dried. It is the substance which I employed in all the ex- 

 periments on the combinations of oximuriatic gas described 

 ih ray last two papers. 



The gas produced by the action of muriatic acid on the Varies vrhea 

 salts which have been called hyperoximuriates, on the con- jj °^^j^j^^^ 

 trary, differs very much in its properties, according as the nates, 

 manner in which it is prepared and coUe61ed is different. 



When much acid is employed to a small quantity of salt, 

 and the gas is collected over water, the water becomes tinged 

 of a lemon colour; but the gas collected is the same as that 

 procured from manganese. 



When the gas is collected over mercury, and is procured 

 from a weak acid, and from a great excess of salt, by a low 

 heat, its colour is a dense tint of brilliant yellow green, and 

 it possesses properties entirely different from the gas col- 

 lected over water. 



It sometimes explodes during the time of its transfer 

 from one vessel to another, producing heat and light, with 

 an expansion of volume; and it may be always made to ex- 

 plode by a very gentle heat, often by that of the hand*. 



It is a compound of oximuriatic gas and oxigen, mixed A compound, 

 with some oximuriatic gas. This is proved by the results 

 of its spontaneous explosion. It gives off, in this process, 

 from ^ to f its volume of oxigen, loses its vivid colour, and 

 becomes common oximuriatic gas. 



I attempted to obtain the explosive gas in a pure form, Attempts t© 

 by applying heat to a solution of it in water; but in this ^ '^ *' ^^** 

 case, there was a partial decomposition; and some oxigen 



* My brother, Mr, J. Davy, from whom I receive constant and able 

 assistance in all my chemical inquiries, had several times observed explo- 

 sions, in transferring the gas from hyperoximuriate of potash, over mer- 

 cury, and he was inclined to attribute the phaenomenon to the combustioix 

 of a thin ftlm of mercury, in contact with a globule of gas. I several 

 times endeavoured to produce the effect, but without success, till an acid 

 vras employed for the preparation of the gas, so diluted as not to afford it 

 without the assistance of heat. The change of colour and expansion of 

 volume, when the effect took place, immediately convinced me, that it 

 was owing to a decomposition of the gas. 



was 



