Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/431

Rh (132.) The alloy which is used for this purpose melts at the boiling point of water, or even below it.

Various degrees of fusibility are requisite for different purposes. The most usual proportions are:—

If the metal is required to be sonorous, 5 oz. tin, 8 oz. bismuth, 8 oz. zinc, 8 oz. brass, and 8 of nitre, are taken. This alloy melts at about the heat of boiling water.

(158.) The caterpillar is said to be either the Tinea Punctata or Tinea Padilla. One insect can work inch of cloth, and the inventor of the art, Mr. De Hebenstreit, in order to give more strength to the cloth, sometimes compels the caterpillars to work several times over the same piece.

(213.) The much admired cast-iron ornaments made at Berlin afford another example of the increased value of the raw material, arising from the labour expended upon it. At the establishment of M. Devaranne, a distinguished manufacturer of cast-iron at Berlin, 10,000 of some of the smaller pieces with which the larger ornaments are composed, are required to weigh one pound.