Elements of physics or natural philosophy, general and medical : written for universal use ... / by Neil Arnott.

  • Arnott, Neil, 1788-1874.
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physics or natural philosophy, general and medical : written for universal use ... / by Neil Arnott. Source: Wellcome Collection.

    154/344 (page 146)
    that the momentary expansion of the newly form- ed water, then in the state of steam, is such as to constitute a violent explosion ; and when a jet of the two gases mixed gives a continued flame, the most refractory substances melt in it like wax in a common taper,—yet these gases may be kept mixed together in the cold reservoir of a blow-pipe with- out combining, and when they art set on fire, while issuing as a jet, the flame does not travel inwards through the opening as might be feared, because it is cooled by the metal of the orifice. A mixture of oxygen and hydrogen passing through the small channels left in a tube filled with wire, may be lighted at the end of the tube without danger of explosion. While solid bodies become very visible or in- candescent at about 1,000° of Fahrenheit, airs, owing to their tenuity of condition, require to be heated much farther before they take on the vivid appearance of flame ; and airs of light atoms, like hydrogen, require to be heated still more than heavier airs. Thus the flame of pure hydrogen is pale and blue, but a wire held in it becomes much more luminous than the flame itself; and the flame of mixed .oxygen and hydrogen escaping from a very minute orifice in a glass tube, may itself be scarcely visible, while the extremity of the tube heated by it becomes like a brilliant star. Hence the light of many flames may be increased by placing a wire gauze or other solid body in the flame ; as is seen when a piece of lime is placed in a flame of mixed oxygen and hydrogen. Con- sideration of this subject enables us to explain