I will give you a few illustrations. Here is a piece of phosphorus, which
burns with a bright flame. Very well; we may now conclude that phosphorus
will produce, either at the moment that it is burning or afterwards, these
solid particles. Here is the phosphorus lighted, and I cover it over with
this glass for the purpose of keeping in what is produced. What is all
that smoke? That smoke consists of those very particles which are produced
by the combustion of the phosphorus. Here, again, are two substances. This
is chlorate of potassa, and this other sulphuret of antimony. I shall mix
these together a little, and then they may be burnt in many ways. I shall
touch them with a drop of sulphuric acid, for the purpose of giving you an
illustration of chemical action, and they will instantly burn[9]. [The
Lecturer then ignited the mixture by means of sulphuric acid.] Now, from
the appearance of things, you can judge for yourselves whether they
produce solid matter in burning. I have given you the train of reasoning
which will enable you to say whether they do or do not; for what is this
bright flame but the solid particles passing off?
[Illustration: Fig. 9.]
Mr. Anderson has in the furnace a very hot crucible,--I am about to throw
into it some zinc filings, and they will burn with a flame like gunpowder.
Pages:
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51