One



Powder some iodine fine, and put a very little of it (about as much as will lie on quarter of an inch of the small blade of a knife) into a small saucer. Pour in enough strong ammonia water to cover it, and let it stand for about 20 minutes. Then either stir the powder up, and filter it (see CHEM- ICAL EXPERIMENTS) or pour off most of the ammonia, and then pour the powder on a piece of blotting-paper. Place the filter-paper or blotting- paper where it will dry in the sun. When it is perfectly dry, rub a stick on the powder, or even brush a feather over it, and it will explode with a crackling noise. Though it has not changed in looks, the iodine has been made by the ammonia into a very explosive substance called Nitrogen Iodide.