a metallic or mineral composition used in soldering or joining together other metals.

Solders are made of gold, silver, copper, tin, bismuth, and lead; usually observing, that in the composition there be some of the metal that is to be soldered mixed with some higher and finer metals. Goldsmiths usually make four kinds of solder, viz., solder of eight, where to seven parts of silver there is one of brass or copper; folder of six, where only a sixth part is copper; folder of four, and folder of three. It is the mixture of copper in the folder that makes solder plate come always cheaper than flat. The folder used by plumbers is made of two pounds of lead to one of block-tin. Its goodness is tried by melting it, and pouring the bignefs of a crown-piece upon a table; for if good, there will arise little bright shining stars therein. The folder for copper is made like that of the plumbers, only with copper and tin; for very nice works, instead of tin they sometimes use a quantity of silver. Solder for tin is made of two thirds of tin and one of lead: but where the work is anything delicate, as in organ pipes, where the juncture is scarce discernible, it is made of one part of bismuth and three parts of pewter.