causing it cracking from cooling it too quickly. The latter risk was chosen and, as feared, because of uneven cooling, the bell was damaged. The present bell is sometimes referred to as Kolokol III (Bell III), because it is the third recasting; remnants from the old bell were melted down and the metal reused to cast the new bell. This practice was fairly commonplace, as the metal materials were very costly. Bell metal was considered so valuable that the first bronze coins for England were made in France out of melted-down old bells. Other metals Other materials occasionally used for bell casting are brass or iron. Steel was tried during the busy church-building period of mid-nineteenth England, for its economy over bronze, but was found not to be durable and manufacture ceased in the 1870s. They have also been made of glass, but although bells of this type produced a successful tone, this substance being very brittle was unable to withstand the continued use of the clapper. By popular tradition the bell metal contained gold and silver, as component parts of the alloy, as it is recorded that rich and devout people threw coins into the furnace when bells were cast in the churchyard. The practice was believed to improve the tone of the bell. This however is probably erroneous as there are no authentic analyses of bell metal, ancient or modern, which show that gold or silver has ever been used as a component part of the alloy. If used to any great extent, the addition would injure the tone not improve it. Small quantities of other metals found in old bell metal are likely to be impurities in the metals used to form the alloy. Decorative bells can be made of such materials as horn, wood, and clay. Casting process The principle of casting bells has remained essentially the same since the 12th century. Bells are cast mouth down, in a two-part mould consisting of the core and a mantle or cope placed over it. These are produced to accurate profiles so an air space exists between them which is filled by the molten metal. Measurement and templating Firstly the bell profile is calculated to exact specifications to ensure it can be properly tuned. Two wooden templates called "strickle boards" are used to shape the moulding clay. One matches the dimensions of the outer bell (called the case