denatured. The gasoline was obtained from a local tank line and 

 was the kind sold for stove and engine fuel. 



The experimental work undertaken with alcohol and gasoline 

 was for the purpose of making a comparison between (i) the 

 heat value of the fuels, (2) their economy in the production of 

 light, (3) their economy in the production of power, and (4) the 

 relative safety of alcohol and gasoline for general use. 



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CALORIMETER TESTS. 



Definition of the British Thermal Unit (B. T. U.) The Brit- 

 ish thermal unit is defined as the amount of heat required to 

 raise the temperature of one pound of water one degree Fahren- 

 heit. This value is definite enough for most practical purposes, 

 however, in or,der to be precise, this one degree of rise is speci- 

 fied as being from 62 degrees to 63 degrees Fahrenheit. This is 

 due to the fact that the specific heat of water varies somewhat 

 at different temperatures. 



Description of Calorimeter. The calorimeter used is one 

 known as the Parr Standard Calorimeter which is of the bomb 

 type and is provided with an electric igniting device. The oxygen 

 for supporting combustion in the bomb is furnished by sodium 

 peroxide. A special accelerator composed of two parts of boric 

 acid and one part potassium nitrate is used with the fuel. When 

 making the tests the proper corrections were made for the heat of 

 the accelerator and other chemical reactions, also the water equiv- 

 alent of the instrument. Each determination was continued long 

 enough to determine the rate of transfer of heat to the air, and 

 ihe readings of the rise in temperature corrected accordingly. 

 These separate calibrations were necessary because it was found 

 impossible to keep the temperature of the room constant. 



Method of Weighing Fuel. The directions for using the cal- 

 orimeter state that when liquid fuels are tested the weight of fuel 

 used may be obtained by using a weighing flask with a dropper 

 tube in the stopper. This method would not cause a perceptible 

 loss in the case of heavy oils, but alcohol or gasoline is so volatile 

 that the following method was resorted to. Small glass bulbs 

 with a capillary tube attached were blown, weighed, filled with 

 fuel, sealed and reweighed. Thus all losses by vaporization were 

 prevented while reweighing and closing calorimeter. The glass 

 of the bulb being inert did not in any way effect the results. 



Heat Produced by the Union of Water and Sodium Peroxide. 

 As stated the alcohol contained about 6 per cent, of water by 

 volume. This water reacts with the sodium peroxide generating 

 heat rapidly enough when placed in the calorimeter to cause the 

 charge to ignite at once. The rapidity of this action was prevented 



