2 WRITINGS OF JOSEPH HENRY. [1824- 



and a stop-cock attached to the other extremity, was firmly 

 screwed into the neck of the vessel; the lower end of the 

 tube dipped into the water, but a number of the holes were 

 above the surface of the liquid, so that a jet of air mingled 

 with water might be thrown from the fountain. The appa- 

 ratus was then charged with condensed air, by means of a 

 powerful condensing pump, until the pressure was estimated 

 at nine atmospheres; during the condensation the vessel 

 became sensibly warm. After suffering the apparatus to cool 

 down to the temperature of the room, the stop-cock was 

 opened; the air rushed out with great violence, carrying 

 with it a quantity of water, which was instantly converted 

 into snow ; after a few seconds the tube became filled with 

 ice, which almost entirely stopped the current of air. The 

 neck of the vessel was then partially unscrewed, so as to allow 

 the condensed air to rush out around the sides of the screw ; 

 in this state the temperature of the whole atmosphere was 

 so much reduced as to freeze the remaining water in the 

 vessel ; the stop-cock and tube at the same time became so 

 cold that the fingers adhered to them, in the same manner 

 that they are sometimes found to stick to the latch of a door 

 on an intensely cold morning. This experiment was ex- 

 hibited to the Institute within six feet of a large stove, and 

 in a room the temperature of which was not less than eighty 

 degrees of Fahrenheit's thermometer. 



LECTURE ON FLAME. 



(Proceedings of the Albany Institute, vol. i, p. 59.) 



March 21, 1827. 



Mr. Joseph Henry delivered a lecture on flame, accom- 

 panied with experiments. 



