Page:Popular Science Monthly Volume 17.djvu/540

524 of tin are fastened to the top of the tube and to the inner rim, as shown in the woodcut, where the middle strip conceals the central tube. There is room inside the circle of test-bottles to place the other bits of apparatus when not in use. The whole construction occupies but a small space, and can be conveniently set aside when not required,



or left in any corner or closet, and covered by a piece of cloth, to protect it from dust. For practice it is placed on any common table, and two pupils can readily use it at the same time from opposite sides. It turns so easily that any test-bottle wanted can be taken and directly returned to its numbered place, so that it is kept constantly in order for continued exercises.

It must not be supposed that this is merely a nice plaything to enable boys and girls to make amusing chemical experiments. Professor Rains had a very serious purpose in preparing it; and it is designed for systematic chemical work. It has been adapted to take pupils through a course of qualitative chemical analysis. Besides the necessary apparatus, there is a sufficient equipment of test-substances for