Some strikingly beautiful results may be obtained in another manner; the method is used by analysts in their so-called fusion tests. We take a small grain of some substance, say, lead nitrate, place it in the centre of our slide, cover with a cover slip, and warm over a flame till it melts. Then, taking a similar-sized grain of another substance, such as saltpetre, we place it against the edge of the cover slip on the side opposite to the lead nitrate. Further warming will cause the saltpetre to melt, and run below the slide and mix with the lead nitrate. If we watch the meeting of the two chemicals a wonderful sight will reward us. The lead compound forms a “beautiful crystalline skeleton,” whilst the saltpetre forms six-sided stars at the opposite side of the cover slip. The experiment may be repeated, using lunar caustic and saltpetre, also the iodides of silver and potassium; in fact we may try any chemical substances we have at hand, though we shall find that some do not melt very easily, and potassium chlorate is somewhat dangerous, for it forms explosive compounds with certain substances. The number of interesting and beautiful objects which may be obtained by so-called solution tests is practically unlimited, and the enthusiastic microscopist will certainly try all the tests we describe as well as many others of his own invention. Should the chemist wish to detect the presence of aluminium in very small quantities, he relies on his microscope and proceeds in the following manner. He takes a drop of the solution, suspected of containing alum, and adds to it a drop of sulphuric acid. This mixture he puts on his slide, which he heats over a flame till dry. Now he adds a drop of water, and then a very small amount of calcium chloride is brought to the edge of the water. Beneath his microscope he can now watch the formation of beautiful colourless, eight-sided crystals which denote the presence of aluminium.