406 SBC. 12. APPLIED MECHANICS. 



Also by making the side removable the amount of both machine and hand 

 work in fitting up the pumps is greatly reduced. The size and weight of 

 any pump (to raise a given quantity of water) are considerably diminished, 

 so that pumps made on this system are far more compact and portable than 

 any centrifugal pumps of the ordinary construction. 



One of Lawrence and Porter's pumps with discharge pipe six inches 

 diameter, and weighing only 3^ cwt., is capable of raising 900 gallons of 

 water per minute, or 54,000 gallons of water per hour. Many of these pumps 

 are now actually at work with highly satisfactory results, and they have re- 

 ceived favourable notice by the scientific press. 



N.B. In the model the side can be removed by simply pulling it gently 

 in a horizontal direction, as the nuts are merely for show, and do not hold it 

 on, and by loosening the small screw in the pulley the disc and spindle can be 

 instantly withdrawn for examination. The patentees will be glad to give 

 further information. 



2064a. Appold's Original Centrifugal Pump and Four 

 trial Discs. Council of King's College, London. 



2066. Archimedean Screw, with glass screw to show the 

 raising of the water. Elliott Brothers. 



2065. Hook's Universal Joint, by which a shaft can be kept 

 in rotation at any angle. - Elliott Brothers. 



2067. Steam Thermometer, for testing temperature of steam 

 in the supply pipes. Elliott Brothers. 



It consists of a thermometer the bulb of which dips into an iron cup con- 

 taining mercury and oil. By this means {he bulb is protected from breakage 

 by pressure, and the thermometer can be removed at any time without letting 

 off steam. 



2068. Air Bell. 



The Committee, Royal Museum, Peel Park, Salford. 



An apparatus consisting of a metal tube 30 feet long, with a percussion 

 pump at one end and a clapper at the other, which rings a bell whenever the 

 piston is struck. [Supposed to be the invention of the late Mr. Gavin 

 M'Murdock, of Soho, Birmingham.] Made by the late Kichard Roberts, C.E., 

 of Manchester, 1840. 



2069. Parallel Motion. 



The Committee, Royal Museum, Peel Park, Salford. 



Consisting of one wheel revolving within another of double its size, and 



carrying a pin whose centre, coinciding with the pitch line of the lesser wheel, 



traverses a straight line equal to the diameter of the larger. [The invention 



of the late Mr. James White, of Manchester.] 1842. 



2O73. Apparatus for supposed Perpetual Motion, used by 

 Dr. Thomas Young. The Royal Institution of Great Britain. 



A wheel supposed to be capable of producing a perpetual motion, the 

 descending balls acting at a greater distance from the centre, but being fewer 

 in number than the ascending ones. "Lectures on Natural Philosophy," 

 by Thomas Young, M.B., 1807. 



