Tyndall's Water-Boiling Apparatus

   This is a Mechanical Equivalent of Heat demonstration. A [missing] belt connects the two pulleys, and allows the smaller pulley to be driven at a high rotation rate as the hand-crank is turned. Projecting upward from the smaller pulley is a thin-walled brass pipe, partly filled with water and closed with a cork. Two pieces of oak, hinged together, surround the pipe and are held in place by the hand of the demonstrator. The work done in turning the crank against the frictional torque serves to heat the water to boiling, whereupon the cork pops out.

   John Tyndall (1820-1893) was a native of Ireland who is best known for his series of lectures at the Royal Institution of London, and the books which he wrote on optics, electricity and heat.

   This apparatus was made by George Prescott & Co. of Dublin, and is in the Callen Collection of Historical Scientific Instruments at St. Patrick's College, Maynooth, County Kildare, Ireland.

   This remnant of the demonstration is at the University of Texas at Austin.It is from the earlier part of the twentieth century and is unmarked.

   The 1928 Welch catalogue describes a similar piece of apparatus as 

   "COUNT RUMFORD'S EXPERIMENT, Tyndall's Friction Cylinder. Cylinder 2 cm in diameter and 10 cm long mounted on a standard rod to fit any rotator chuck and with a wood, calf-lined friction clamp. Alcohol cam be made to boil in a short time so as to blow out the cork from the tube .. $2.00"

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