The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated form the 5th German edition by C.H. Peirce.

  • Stöckhardt, Julius Adolph, 1809-1866.
Date:
1851
Catalogue details

Licence: Public Domain Mark

Credit: The principles of chemistry : illustrated by simple experiments / by Julius Adolph Stöckhardt ; translated form the 5th German edition by C.H. Peirce. Source: Wellcome Collection.

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    lamps. It is well known that narrow chimneys draw better than wide ones; the air escapes from the former hotter and more rapidly; hence a greater quantity of cold air is supplied to the fire, causing it to burn more freely. Experiment. — If the upper part of the cylinder of a lamp be divided into two channels by a partition down the middle, the candle will then burn, even if access of air be cut off from below. The smoke of a glimmering taper will be drawn inwards on one side and expelled from the other, as indi¬ cated by the arrows in the fig¬ ure; a draught of air sets in from the top to the bottom, which supplies the oxygen requisite for combustion; that this current of air exists is also made evident by the quiver¬ ing motion of the flame. 112. In common lamps air has access only to the outside of the flame; hence combustion goes on only at the circumference, and not simultaneously in the interior, as is indicat¬ ed by the dark central portion. But if air be admitted into the interior of the flame, this dark portion disappears; then a more complete combustion is effected, with the production of increased light. On this principle the so-called Argand lamps are constructed, to which are adapted circular wicks, so that the air has access, not only to the-exterior surface of the flame, but is ad¬ mitted from below directly through the cen- n