Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    44/768 (page 32)
    3* or POTASH be established almost exclusively by the agency of water; the proportion of oxygen with which the potassium com- bines is about 20 with 100 parts: hence potash consists of one atom of its metallic base, 40, and one of oxygen, 8, and its equivalent is 48. There is, lastly, a product obtained from the oxygenation of potassium, by inclosing it for some days in a small vessel loosely covered, which is dull, brittle, and inflammable; it appears, like that ob- tained by Sir H. Davy, to be a mixture of potash and potassium. From its strong attraction to oxygen, potassium acts with energy on wxter, presenting the striking phenome- non of a body taking fire when dropt upon water; the water is rapidly decomposed ; an explosion is produced with a bright flame; hydrogen gas is evolved; and the potassium is converted, by oxygenation, into potash. Placed on ice, it burns with a bright flame, melting the ice. It attracts oxygen, with similar rapidity, from the mineral acids, and burns. With the aid of heat, potas- sium can abstract oxygen from almost every substance containing it, and also from various oxidated substances. It thus changes the constitution of the other alkalis and earths. Its action on ammonia is singular. When heat- ed in it, the ammonia disappears, hydi’ogen gas in a simi- lar volume is produced, and an olive-coloured substance is formed, considered by Gay-Lussac and Thenard to be a compound of potassium with nitrogen and ammonia. Potassium burns, when heated in chlorine gas, with a vivid flame ; a chloride of potassium is the result; it is the same substance as muriate of potash when dried; and as its chemical properties can be known only when it is in the state of solution, as muriate of potash, a separate de- scription of it is unnecessary. In like manner, when iodine and potassium are heated together, they unite with l