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.

    134/768 (page 122)
    /mV IN Iron wire supported Copper, Platina, Silver, Gold,, Zinc, Tin, Lead, v r. k kWV/kWW ^ ■ WkWT/WkVW Pounds. 549.25 302.278 274.32 187.137 150.753 109.54 34.63 27.621 The quality of hardness belongs to the metals, but is possessed by the different metals in^very different degrees. In all of them it can be increased by artificial methods, principally by cooling them suddenly when they have been highly heated. The hardness acquired from this hasty approximation of the particles is accompanied with a cor- responding degree of brittleness. The softness and tena- city can be restored by again heating them, and allowing them to cool slowly, a process which, when performed with this view, is termed Tempering. In their relations to caloric, metals observe the same 1 general laws as other bodies. • They are superior to all others in conducting power; they also excel others in power of reflecting caloric, while they do not radiate so perfectly, nor absorb radiant heat with such facility. Their fusibility is very various. Quicksilver is so fusible as to require a reduction of temperature equal to —40° to congeal it; while other metals, as molybdena, titanium, or platinum, can with the utmost difficulty be fused. In congealing, they so far assume a crystalline arrangement, as to exhibit an internal structure peculiar to each. Iron, for instance, has been, shown by Mr Daniell to have a fibrous texture, bismuth and antimony a lamellar, and steel a granular texture. By melting, and then slowly cooling them, several of the metals can be made to assume regular