80 SEC. 3. MEASUREMENT. 



meter is also kept in motion by the difference of pressure. The frictional 

 resistance is the same with all pressures of the fluid under measurement, and, 

 according to the size of the meter, is represented by a water head of 3 to 

 16 ft. The different parts of the meter are constructed of materials not 

 liable to chemical influence. 



The chief advantages of this meter are : 



1. The velocity of the engine is exactly in proportion to the quantity 



flowing through the meter. 



2. According to the most careful experiments, the error, if any, does not 



exceed 1 per cent. 



321a. Siemens' and Adamson's Patent Water Meter. 



Guest and Chrimes, Rotherham. 



This meter has a great resemblance to the motive-power machine known as 

 Barker's Mill. The water passes down through a funnel into the measuring 

 drum, and in passing outward through the curvilinear channels of the 'same 

 causes it to revolve, delivering a certain quantity of water at each revolution 

 of the drum, and this is indicated by worm wheel and gearing, in gallons, feet, 

 or any other units required, on a dial plate properly divided and prepared 

 for the purpose. 



The meter is exhibited in section, so that the internal arrangements and its 

 action can be seen. This meter has been extensively used for upwards of 20 

 years. 



32 lb. Half-inch Patent Water Meter, for the water supply 

 for domestic and trade purposes on the constant supply system. 



J. Tylor and Sons, London. 



326. Water-meter, for cold water, for 26 mm. width of 

 tube. Dreyer, Rosenkranz, and Droop, Hanover. 



327. Water-meter, for domestic use. 



Dreyer, Rosenkranz, and Droop, Hanover. 



331. Model of a Gas Meter of ancient construction, with 

 glass sides. 



School for Industry, Halle (Dr. Kohlmann, Director). 



329. Apparatus for determining the capacity of Car- 

 tridge-cases as far as 20 cub. mm. A. Bonsack, Berlin. 



330. New Volumeter, consisting of A. Sauer's burette, 

 a second glass piece, stands and tubes. 



(Compare Fresenius, " Zeitschrift fur analytische Chemie," xiv. 

 heft. 3 and 4). 



Berggewerkschafts-kasse, Bochum, Dr. Heintzmann. 



