262 



Chemical Instruments and Operations. 



New Eudiometrical process hy means of Nitric Oxide. 



Suppose a tube of about three inches in diameter, and two 

 feet in height, closed at one end, to be marked by a diamond 

 at the point to which it becomes charged, by receiving, 

 when filled with water, over the hydro-pneumatic cistern, 

 nine hundred measures of air, from the sliding rod gas mea- 

 sure, 127, also, at th« point to which it becomes charged af- 

 ter receiving one thousand such measures. Into the tube 

 thus prepared, while filled with water and inverted over the 

 hydro-pneumatic cistern, introduce one thousand measures 

 of air. Then add five hundred measures of nitric oxide, by 

 means of a volumeter, holding exactly that quantity. After 

 the red fume produced by this addition is washed away, by 

 agitation with the water, there will be about eight hundred 

 and fifty measures left. This will appear, upon adding from 

 the sliding rod gas measure as many measures of hydrogen 

 as are necessary to cause the residual air to extend to the 



