Editorial note — From Chambers's Journal. Thermometers.

[Footnote 246: Mr. Balfour Stewart has lately concluded a series of experiments at the Kew Observatory, by which he has accurately determined the freezing-point of mercury. The experiments, conducted with great care, have shown that the freezing-point of mercury, like that of water, is constant, and that it denotes a temperature of -37.93 F. The freezing-point of mercury will now be used as a third point in graduating thermometers which are intended to register extreme temperatures.]