Wollaston, William Hyde (1766–1828)

English chemist and physicist who discovered in 1804 how to make malleable platinum. He went on to discover the new elements palladium in 1804 and rhodium in 1805. He also contributed to optics through the invention of a number of ingenious and still useful measuring instruments.

Wollaston was born in East Dereham, Norfolk, and studied medicine at Cambridge.

Wollaston initiated the technique of powder metallurgy when working with platinum. Using aqua regia (a mixture of concentrated nitric and hydrochloric acids), he dissolved the platinum from crude platina, a mixed platinum–iridium ore. He then prepared ammonium platinichloride, which he decomposed by heating to yield fine grains of platinum metal. The grains were worked using heat, pressure, and hammering to form sheets, which he sold to industrial chemists. He donated much of the profits to various scientific societies to help finance their researches.

In 1807 he developed the camera lucida, which was to inspire William Fox Talbot to his discoveries in photography.

A supporter of John Dalton's atomic theory, Wollaston suggested in 1808 that a knowledge of the arrangements of atoms in three dimensions would be a great leap forward.

As a member of a Royal Commission in 1819, Wollaston was instrumental in the rejection of the decimal system of weights and measures.