OCR Text |
Show Bell Manufacture The metal from which bells are usually usu-ally made (by founding) Is an alloy, called bell-metal, commonly composed of SO parts of copper and 20 of tin. The proportion of tin varies, however, from one-third to one-flfth of tha weight of the copper, according to the sound required, the size of the bell and the impulse to be given. The clearness and richness of the tone depends upon the metal used, the perfection of Its ranting and also upon Its shape. It har-ing har-ing boeii shown by a number of experiments experi-ments that the well known shape with a thick lip Is the best adapted to give a perfect sound. The depth of the tone of a bell Increases la proportion to Its size. |