Page:Popular Science Monthly Volume 8.djvu/628

610 For the purpose of, suspension an arrangement resembling a towel-horse, with a single horizontal rail, will be found convenient.

h. A straw, I I', Fig. 2, delicately supported on the point of a sewing-needle N, inserted in a stick of sealing-wax A, attached below to a little circular plate of tin. In Fig. 3 the straw is shown on a



larger scale, and separate from its needle. The short bit of straw in the middle, which serves as a cap, is stuck on by sealing-wax.

i. The name of "amalgam" is given to a mixture of mercury with other metals. Experience has shown that the efficacy of a silk rubber is vastly increased when it is smeared over with an amalgam formed of one part by weight of tin, two of zinc, and six of mercury. A little lard is to be first smeared on the silk, and the amalgam is to be applied to the lard. The amalgam, if hard, must be pounded or bruised with a pestle or a hammer until it is soft. You can purchase sixpennyworth of it at a philosophical-instrument maker's. It is to be added to your materials.



k. I should like to make these pages suitable for boys without much pocket-money, and therefore aim at economy in my list of materials. But provide by all means, if you can, a fox's brush, such as those usually employed in dusting furniture.

Electric Attractions.—Place your sealing-wax, gutta-percha