695 



degree, and if the pit be close it recoils on 

 the ice for want of a vent. If the close pit 

 is not frequently opened it becomes very 

 warm, and the ice is soft and pappy at the 

 top . The deepest and coolest pits are about 

 twenty degrees warmer than the freezing 

 point : so that no depth of a pit can pre- 

 serve ice from melting. It is from a greedi- 

 ness for depth that we too often meet with 

 damp earth. 



Some years afterwards, I made another 

 ice-house, 15O yards from the above-men- 

 tioned, on the principles and in the man- 

 ner following : Vent was an essential ob- 

 ject ; and dry ness with coolness led me to 

 the design of insulating the mass with a bed 

 of straw surrounding a pen of logs which 

 was to contain the ice. The pit was dug 

 on a spot open to wind and sun, for the 

 sake of dryness. It was nine feet deep. 

 Within it was the pen of logs, of that depth, 

 and nine feet square in .the clear. It con- 

 tained but a little more than 700 solid feet 

 only half the quantity stored in common 



