12 BULLETIN NO. 161 



CARBON DIOXIDE AS A SMUDGE WITH THE 

 ADDITION OP HEAT 



Near the center of the Mechanic Arts building of the College 

 there is a space of 500 square feet that is surrounded on all 

 sides by one story brick walls and yet is open at the top. Ther- 

 mometers were distributed in this space and a like number were 

 placed in the open country away from the building. The ther- 

 mometers were read at regular intervals after the sun went 

 down as the air in both places cooled. They both cooled at the 

 same rate, the mean temperature inside remaining almost ex- 

 actly the same as the mean of the outside thermometer read- 

 ings. By means of a hose, carbon dioxide gas was liberated 

 throughout this space as fast as we could get it to run out of 

 the tank, the neck of the tank being surrounded by cloths kept 

 soaked with hot water to prevent the opening to the tank from 

 freezing up- The mean temperature inside remained the same 

 as that outside, both cooling of course as the night progressed 

 but both cooling at the same rate. The carbon dioxide appeared 

 to be valueless as a blanket for holding the heat inside the 

 inclosure. 



AMOUNT OF HEAT REQUIRED TO WARM AIR 



Six heaters were distributed in this inclosure and were con- 

 nected so that the electrical power transformed into heat was 

 40 K. W. Five thermometers were distributed in the space 

 and hung up about five feet above the ground. A like number 

 were placed away from the building at the same elevation above 

 the ground. As a result of six experiments, each one running 

 for two to three hours, and the thermometers being read every 

 ten minutes, the mean temperature of the outside section being 

 52o F. it was found that the air inside was maintained six 

 degrees Fahrenheit warmer than the air outside. An anemome- 

 ter was used to give the wind velocity, and in spite of the fact 

 that the heated area was sheltered or protected on all sides, the 

 wind was unusually effective in cutting down the rise in tem- 

 perature inside the heated area. The wind velocity varied from 

 a calm to ten miles an hour and in the case of the latter wind, 

 the rise in temperature was but 2-9 F. while with no wind the 

 temperature inside exceeded that of the check thermometers 

 outside by 9.6 degrees, the mean of all the experiments being 

 as stated above six degrees. The wind velocity was measured 

 on top of the building. Assuming the rise in temperature to 

 be proportional to the amount of heat supplied which as- 



