Compounds of Nitrogen. 511 
nitrate, was added to prevent the deflagration 
from being too rapid. The mixture was put 
into a green glass tube of the diameter of a 
common quill, into the upper part of which, 
before bending it so that it might pass be- 
neath the mercury of the trough, a known 
weight of iron wire coiled into a spiral form 
was introduced. Under this part of the tube 
a double row of burning spirit lamps with 
flat wicks was placed; and when the iron 
wire appeared red hot, the mixture at the bot- 
tom of the tube was heated by another lamp, 
at first moderately to expel any moisture, that 
might have been absorbed from the air while 
the tube was being filled, and then more 
strongly so as to set the mixture on fire. By 
slowly moving the flame of the lamp under 
that part of the tube which contained the 
mixture, from above downwards, the com- 
bustion'spread gradually through the whole, 
and the gaseous products were not more ra- 
pidly evolved than was consistent with their 
being wholly collected. They proved to be 
more complicated than I expected; for not 
only carbonic acid and nitrogen were obtained, 
but nitrous gas, carbonic oxide, anda very 
small quantity of hydrogen, the last of which 
would indicate the presence of water in the 
