The decomposition of ammonia by heat.

This subject has been already dealt with by Ramsay and Young, who heated ammonia in glass tubes at various temperatures, and found that decomposition began under the most favourable circumstances at a little below 500°, and that the amount decomposed depends on the extent of the heated surface of the solid with which the ammonia is in contact, on the nature of the surface, and on the time of exposure to heat. We have thought it desirable to extend our knowledge of the subject still further by investigating the rate of decomposition at various temperatures. The ammonia was contained in porcelain vessels heated in a muffle furnace, and the decomposition was traced by reading the pressure on a mercury manometer, the sum of the volumes of the ammonia and products of decomposition being kept constant.