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Lat. In Roman law. The sale per ces et libram (with copper and scales) was a ceremony used in transferring res mancipi, in the emancipation of a son or slave, and in one of the forms of making a will. The parties having assembled, with a number of witnesses, and one who held a balance or scales, the purchaser struck the scales with a copper coin, repeating a formula by which he claimed the sub- ject-matter of the transaction as his property, and handed the coin to the vendor.