378 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



distance ; whereas, for mere refrigeration any ice will answer 

 equally well. It appears to me desiraLle to inquire whether 

 mechanical methods, such as the compression of air, may not be 

 used, so that coal, instead of ice, may be used for cooling. 



Mr. Dibben. — The cooling of houses by ice is not new. Though 

 it may not be in use for cooling private residences, yet it is used 

 to a considerable extent in this city for cooling packing-houses, 

 where they cut up and pack in the summer time thousands of 

 tons of fresh meats, simply by having a good non-conducting 

 exterior to the house, having double or triple windows, and 

 having a reservoir or cistern of ice for the air to pass through. 

 The temperature in that way may be kept down to forty or fifty 

 degrees all through the summer. But as a practical thing in 

 our houses, I doubt whether it would be beneficial to our health. 

 Generally in the summer season, the air is within eight or ten 

 degrees of the dew-point, or point of saturation. Lower the air 

 ten degrees, and it would begin to deposit moisture. I am 

 inclined to think that this moisture would produce various 

 derangements of the human system. Again, we must remember 

 that in order that the cooling of the air should be economical, 

 the windows must be closed. 



For the large cities, Charleston, Savannah, New Orleans, 

 wherever there is direct communication with the Hudson river 

 and with Boston, there can be no competition in the making of 

 ice. But for small country towns an ice machine might perhaps 

 be worked to advantage. 



Mr. Koch described an apparatus for producing ice artificially, 

 consisting of two hollow splieres connected by a pipe. One of 

 the spheres contains ammonia, and the other is submerged in 

 water. By the application of heat the ammonia is evaporated 

 until the pressure is sufficient to liquify it upon the other side. 

 As soon as the heating apparatus is taken away, the ammonia 

 becomes vapor and goes back. This would freeze the water. 

 Then the process may be repeated. 



Mr. Seely suggested that the change of temperature desirable 

 in summer is very far less than that in winter, so that the same 

 means will produce a far greater effect. Mr. Dibben's objection 

 appears far more formidable than the mere question of cost. 

 But the operation would be such as to prevent the air from 

 becoming so moist ; for in passing over the ice the air becomes 

 cooled and immediately deposits its excess of moisture upon the 



