Ponderous Spar, Barytes; or heavy earth, a name given to a fossil naturally combined with the sulphuric or carbonic acids, and found in different parts of England, particularly in the counties of York and Derby.

This mineral is manufactured into vases, and other ornaments for chimney-pieces; but its principal use in domestic economy, having been already stated, vol. iii. p. 475, we shall only remark, that the ponderous spar may be procured in a very pure state, for medicinal purposes, by the process which ya u-QUELiN and Fourckoy have adopted; and a translation of which has been given in Mr. NichOl-son's Journal of Natural Philosophy, etc. vol. i. p. 535. - It would, however, be hazardous to mention the disorders, and doses, in which this powerful remedy is employed; hence parents should not suffer children to use the picture-frames, egg-stands, and other trinkets made of Derbyshire spar, by way of playthings.