S80 Mr Beuch^r 6n the Nature of Flame, 
found, upon repeated trials in this way,' using the tube 15 
inches long, as shewn on Plate IX. Fig. 1. that the flame could 
pass through 0, 6, 9 and 12 pieces at once ; these being placed 
1, 2, 3 and 4 pieces at each of the joinings 6, and c. 
Eoop, 15. — Although, by the two last experiments, it was 
proved that the flame could pass through the coarser wire- 
gauze when increased even to 12 pieces, yet it did not follow 
that it was not thereby altered somewhat in its nature. A pro- 
bable change was, that it might become inert with regard to in- 
flammables, as takes place in the several safety lamps, and par- 
ticularly that of Sir Humphry Davy. Several experiments 
were tried, to ascertain if this suggestion were correct ; first, the 
wire-gauze was put at a ; then at a and h ; and lastly, at «, h 
and c ; placing at the same time, during each trial, a quantity 
of gunpowder in a piece of flannel at the bottom of the tube ; 
and in all of these it was found that the gunpowder was infla- 
med, and the wire-gauze not in the least injured. 
Exp. 16. — The result was next tried, firing the fulminating 
powder, whilst the finest wire-gauze was placed first at a, then 
at a and h, and then at a, h and c, and it was found that the 
flame still appeared at the bottom ; shewing that the gauze, al- 
though much finer than that used in Sir Humphry Davy’s safe- 
ty lamp, was not impervious to this flame. In some of the ex- 
periments a hole was found to have been made in the centre of 
the wire-gauze, and sometimes the parallel wires were forced 
wider. This was very often the case, when a piece of wire- 
gauze was put at all the joinings, a, h and c, and then it was 
the gauze at a which was torn, or otherwise injured. 
Exp. 17. — In order to ascertain if the flame stiU remained 
unaltered, notwithstanding its having passed through the finest 
gauze, a quantity of gunpowder in flannel was affixed to the 
bottom of the apparatus, and it was inflamed through one, two, 
and even three pieces of the gauze. Here the same occasional 
appearance, noticed in the last experiment, occurred, with regard 
to the upper piece of wire-gauze. 
V. Before the discovery of the powder which has been since 
used, a mixture of equal parts of the impure antimony of com- 
merce and super-oxymuriate of potassa was employed, which 
