Platinum and Palladium in Astronomy and Navigation

Astronomy and navigation depend to a large extent on the ability to measure angular displacements with a high degree of accuracy, and since early times instrument makers have sought to improve the usefulness of their products by innovation. Shortly after ingots of malleable platinum and palladium became available commercially in England it was realised that these new metals had properties which were superior to those of silver, upon which the scales used for measuring angles were then engraved. The use made of platinum and palladium by one London firm of instrument makers in the first half of the nineteenth century is considered here.