Copy 2

The naturalist's and traveller's companion, containing instructions for discovering & preserving objects of natural history and for promoting inquiries after human knowledge in general / [Anon].

  • Lettsom, John Coakley, 1744-1815.
Date:
1774
Catalogue details

Licence: Public Domain Mark

Credit: The naturalist's and traveller's companion, containing instructions for discovering & preserving objects of natural history and for promoting inquiries after human knowledge in general / [Anon]. Source: Wellcome Collection.

    64/134 (page 34)
    YL METALLIC SUBSTANCES. a. Iron is a common ingredient in mineral- waters, whence they are called chalybeate. The general method of diftinguifhing this metal, is* by an infufion or powder of galls, which turns water containing iron of a purple or black co¬ lour, deeper in proportion to the quantity of iron prefent. But the moft accurate method, is by means of the Pruffian alkali (x) fully faturated with the inflammable matter of dried blood. This al¬ kali mixed with a chalybeate water turns the latter immediately blue, and depofits the iron in; a powder of the fame colon k Copper in water is precipitated in a red powder by the fame alkali, c. Zinc is precipitated in a white powder by the Pruffian alkali. Although this alkali preci¬ pitates all the metallic fubftances from acids, fa that they may be diftinguifhed from one another3. it does not any of the earths, do Arsenic has been fufpefted in fome mineral iprings, but I am acquainted with no proof of ite However, it may poffibly happen that water running through arfenical veins, may carry off a quantity of arfenko To difcover this, the water C*) The Pruffian alkali is made of equal quantities of dried ox-blood, and fixed alkali. Thefe are to be burnt together in a crucible, and the allies diffiolved in a fufficient quantity of water, when we enter on our experiments. ffionld