404 [Assembly 



however, so far south as New-York or its vicinity, but the cold 

 here is barely sufficient in average winters. The process of 

 freezing also requires sonoe little attention to shut off the water 

 when the temperature is 30° Fahrenheit, or more, and to keep 

 the house covered in case of storm or warm weather. 



My theory in regard to ice houses is that they want, not large 

 capacity, but complete protection. Of course, a large body of ice 

 will keep longer under the same circumstances than a small one. 

 JBut a six feet cube of ice can be made to serve the wants of an 

 ordinary family for the season perfectly well. In such a case the 

 walls should be thirty or thirty-six inches thick above ground, 

 if filled with saw dust, sand or gravel (half that perhaps if filled 

 with charcoal dust), the roof double and as tight as possible (I 

 use a single canvass roof myself for lightness), and a perfect 

 drainage, but without any communication of air through the 

 drain. Under ground ice houses will always do well if they have 

 a good blind drainage, either natural or artificial, and a little 

 sand or gravel, perhaps, between the side planking and the earth 

 walls, if the earth is wet. The floor should be of gravel, plank 

 flooring only serves to give a circulation of air completely round 

 the body of ice, which is not particularly favorable to its presei- 

 vation. Air spaced walls are not good for ice houses, I think, 

 notwithstanding so good an authority as Professor Mapes. The 

 air, being highly mobile, is put in rapid circulation by the heat 

 of the external wall, which is, perhaps, exposed to the direct 

 rays of the sun, and communicates that heat to the inner wall, 

 and thus to the ice within. If the air could be kept motionless 

 in such a space it would answer an excellent purpose. But con- 

 sidering its extreme mobility, a four-inch space were much better 

 filled with some such material as saw dust than left empty. But 

 such a wall would be good for nothing for an ice house in either 

 case. 



Bat I have been betrayed by this matter into a long communi- 

 cation when I only took my pen to ask a description of " balloon 

 frames." Respectfully yours, 



SAMUEL H. ALLE.'^. 



