some more which has been soaked in nitrate of copper—it does not burn quite so brightly, but still very beautifully. In all these cases the combustion goes on independent of the oxygen of the atmosphere. And here we have some gunpowder put into a case, in order to shew that it is capable of burning under water. You know that we put it into a gun, shutting off the atmosphere, with shot, and yet the oxygen which it contains supplies the particles with that without which chemical action could not proceed. Now, I have a vessel of water here, and am going to make the experiment of putting this fuse under the water, and you will see whether that water can extinguish it. Here it is burning out of the water, and there it is burning under the water; and so it will continue until exhausted, and all by reason of the requisite amount of oxygen being contained within the substance. It is by this kind of attraction of the different particles one to the other that we are enabled to trace the laws of chemical affinity, and the wonderful variety of the exertions of these laws.
Now, I want you to observe that one great
