Proceedings of the Polttechxic Associatiox. 901 



through valves into the fan, and throngh a box is carried to the 

 furnace. Mr. Parrish said he was twenty-one years and two months 

 in getting his patent ! The ventilator was intended to be run with 

 springs or weights, and one winding could easily be made to run thirty- 

 six hours. The pendulum as its name indicates, vibrates, and the fan 

 at the end of the rod causes the required commotion in the air. The 

 width of the fan for ordinary use will be five feet long and three feet 

 wude, which will heat a room at one-third less cost than any other plan. 



Mr. C. E, Emery did not see why this apparatus should take less 

 fuel to heat a room than any other contrivance. The fan being five 

 feet long, from his calculation it would take ten strokes a minute to 

 supply sufficient fresh air for fifty people. 



Mr. John Johnson remarked that twenty-five cubic feet of air per 

 individual per minute, and the lowest estimate is thirteen feet per 

 minute. This is the amount supplied to the House of Representatives, 

 in Washington. It is laid down as essentially necessary to have from 

 fifteen to twenty feet per minute for all public buildings. The 

 English Houses of Parliament and our Congressional Halls have 

 appliances for doing this. 



Electeicity. 

 Dr. Yanderweyde performed some experiments with an electrical 

 machine, and said : We have thus far considered air an isolating sub- 

 stance which prevents electricity from passing off from bodies. 

 Electricit}^ will not pass the distance of a quarter of an inch in a 

 vacuum. This shows that there is no such thing as the electric fluid. 

 A glass tube being exhausted of air by an air pump, and then filled 

 with oxygen gas ; the tube then being made red hot, shows that 

 there is no such thing as caloric fluid, as the old books state ; and is 

 only a mode of atomic motion, as motion can be transferred into 

 heat. Electricity is now known to be a state of matter. (Dr. Y. 

 exhibited a frictional electrical machine, the frictional plate being 

 made of vulcanized India rubber.) The metal, he said, does not 

 contain the charge, but it is on the surface of the glass, and not on 

 the metal. The air touching the aclass is also charo-ed, more in sum- 

 mer than in winter. It has been proved that the air contains ten 

 times more electricity in winter than in summer ; and where there is 

 no air there is no electricity. To prove that electricity does not pass 

 through a vacuum, he connected M'ith the electrical macliine a glass 

 tube filled with air, the points of tlie platinum wires being about 

 three-fourths of an inch apart, and brilliant flashes of elcQtric light 



