FARM BUILDINGS. 317 



ished temperature ; it follows, that air which is near the 

 freezing point, if sustained by tight walls, cannot be displaced 

 by warmer air, unless a current is forced upon it from with- 

 out, which must be avoided. As well may mercury be 

 driven out of a vessel by pouring water into it. The cold 

 air settles upon the ice and remains there permanently, and 

 of course the ice has no tendency to melt even during the 

 hottest weather. By adhering to these principles, ice may 

 be kept for years, and almost without waste. It is important 

 to put up ice in the largest, most compact blocks, and in the 

 coldest weather. By the use of large pieces closely wedged 

 together, there is security against the circulation of air 

 through the mass ; and by doing this in the severest weather, 

 the ice goes into store with a greatly augmented intensity of 

 cold. Some do not consider the difference in the tempera- 

 ture either of snow or ice, when each are equally susceptible 

 of degrees of temperature below 32, as the atmosphere, 

 metals, or other substances. If put into the store room at 

 zero, ice must be elevated 32 before it rises to the melt- 

 ing point, and it has, therefore, all this stock of cold (priva- 

 tion of heat) which it must first exhaust, before it assumes 

 the form of a liquid. A rigid observance of the above rules, 

 will preserve ice anywhere, either above or below ground. 



The materials for farm buildings I have assumed to be 

 of wood, from the abundance and cheapness of this material 

 generally in the United States. Yet when not too expen- 

 sive, or where capita] can be spared for this purpose, brick 

 or stone should always take their place. They are more 

 durable, less exposed to fire, and they sustain a more equable 

 temperature in the extremes of the seasons. 



Barns and sheds cannot, like houses, be conveniently made 

 rat proof, but they may be so constructed as to afford them 

 few hiding places, where they will be out of the reach of 

 cats and terriers, which are indispensable around infested 

 premises. These and an occasional dose of arsenic, care- 

 fully and variously disguised, will keep their numbers within 

 moderate bounds. If poison be given, it would be well 

 to shut up the cats and terriers for three or four days until 

 the object is effected, or they, too, might partake of it. 



LIGHTNING- RODS. 



During the sultry weather of American summers, thunder 

 showers are frequent and often destructive to buildings. 

 This danger is much increased for such barns as have just 



