Mayer's, entitled 'Beitraege zur Dynamik des Himmels,' Heilbronn, 1848; 'Bemerkungen ueber das Mechanische Equivalent der Waerme,' Heilbronn, 1851. ==================== IN MEMORIAM.--Dr. Julius Robert Mayer died at Prattsburgh, Steuben county, New-York, on September 22, 1877, was long prevalent among mechanicians. Many of the dial plate of colourless glass, moreover, transmits 68 per cent. Of the.