Freezing Water

1847 Scientific American  
SCIENTIFIC AMERICAN. '1'0 render visible the opposite currents Into which Fluids are t.hrown whilst tkey chan ge their te"'perature. Fill a common e i ght-ounce phial, or cylin drical gla�s jar, but 2 i nches 01' more in diam· eter, and fiv e or six inches lon g, with cold wa ter, and diffuse through it a small portion of pulverized a mber : let tbe phial of water be immersed into a tumbler, 01' larger vessel, contain i ng hot water ; this being done, two currents, going in different
more » ... ifferent directions, will be observed in tbe inner vessel, the one ascend ing, and the otber desce n di ng ; that is to say the minute par ticle s of amber, which were dIffused through the fluid, an d were at rest befo:e the heat was appl ied to the water in th e inner vessel, will be seen in motion ; those particles thll.t are situated towards the side of the glass, or which are nearest to the source of heat, will move upwards, whilst those that are in the centre move downw ards ; and thus two distinct currents are fo rmed in opposite directions ; the central one being directed downwards, and the exterior one upwards. These curre nts gradu ally diminish in v el ocity and, when the water in the inner ve ssel has acquired tbe same temp eratm e as that in the outer one, the particles of amher will again be brought to a state of rest.
doi:10.1038/scientificamerican08141847-376i fatcat:bs7k3gnm6jgpvjbb5mpboubwnq