Proceedings of the Polytechnic Association. 851 



though not strictly necessary, to have a surface condenser, from which 

 to collect and measure the distilled water, and thus, in two ways, 

 ascertain the quantity of steam used. The power of the engine should 

 be measured both by the indicator and dynamometer, and duplicate 

 registers should be provided to count the revolutions. The better 

 plan, in order to give the same area of indicator diagram, is to use, in 

 each experiment, a cut-off, fixed at any desired point, and not use the 

 governor. In such case, special means must be provided to keep up 

 a uniform lubrication, which, with the unitbrm resistance proposed, 

 will secure uniform speed. 



When experimenting, the coal should be weighed, and the feed 

 water measured, or weighed, with all the accuracy required for test- 

 ing boilers. At the same time, indicator diagrams should be taken 

 at least once an hour, and the reading of the dynamometer recorded. 

 A record should also be kept of the time, revolutions of engine, 

 steam pressure, and the temperature of the feed water, and in a con- 

 densing engine, of the hot well and circulating or condensing water. 

 The temperature of the engine and fire room, and of the external 

 ail', should also be noted, to show the effect on condensation in the 

 pipes and passages. The direction and force of the wind is also use- 

 ful, to show its influence on the fires. Barometrical observations are 

 essential, to show the true zero of the steam pressures. Experiments 

 conducted thus carefully, and with such apparatus, would furnish 

 results of the greatest value to science. Each trial would show the 

 economy of the boiler and of the engine, also the friction of the 

 engine and its load, and the net power and its cost ; besides affording 

 much valuable information to aid in the explanation of the losses 

 which now exist in the steam engine, and suggesting improvements 

 in its construction. The United States expansion experiments were 

 tried, substantially, on this plan, but were stopped when results were 

 being obtained of the greatest interest. Could an experimental 

 establishment be now opened to manufacturers and inventors, how 

 much capital, physical exertion, and mental anxiety could he saved, 

 and how greatly the steam-engine might be improved. Without 

 such a place, however, much good can be done, if ever}' engineer 

 will carefully use the means at his command, and record the results. 

 The awards at all our fairs should be based upon trial, and not upon 

 mere opinion. 



The " yankees " are an ingenious people. Let all assist in direct- 

 ing this ingenuity into scientific channels, and the character of the 



