EGGS IN COLD STORAGE. 53 



which will be advertised in Ice and Refrigeration, the 

 writer believes it to be head and shoulders above any- 

 thing else in this line, and does not hesitate to recom- 

 mend it to those wanting- a door which will prevent 

 air leakage. The price is very reasonable, consider- 

 ing- the excellent material and fine work put into its 

 construction. The slig-ht additional cost over the 

 common door will be quickly saved, by reason of its 

 quick action opening- instantly when the lever is 

 grasped. 



Having- g-ot into the subject of air leakag-e, we may 

 as well see how it is caused and why it must be airleaka ^ e - 

 g-uarded ag-ainst. It is operative from the same law 

 as gravity air circulation, which was explained quite 

 thoroug-hly in the first part of the chapter on " Circu- 

 lation." When the outside air is warmer than that 

 of the storage room, the air in the storage room pro- 

 duces a pressure on the floor and lower part of the 

 room, by reason of its greater weight, and conse- 

 quently it seeks to escape there. If there are open- 

 ings near the floor where the air can flow out, and 

 others at the ceiling -or upper part of the room, the 

 air will flow in at the top and out at the bottom of the 

 room. Reverse the conditions of temperature, and 

 the direction of flow of air is also reversed. That is, 

 when the air outside is colder than the air of the 

 room, the cold air will flow into the room at the bot- 

 tom and the comparatively warm air of the room out 

 at the top. This action is nicely illustrated by not- 

 ing the air currents in a door which is opened into a 

 cold room when the temperature is very warm out- 

 side. The warm air rushes in at the top of door and 

 the cold air of room out at the bottom. In cold 

 weather the direction of air flow will be reversed. 



Perfect inclosing walls for a cold storage room 

 would be perfectly air tight, as they would be if lined stora ^ e 

 with sheet metal, with soldered joints. The interior 

 conditions would then be under more perfect control. 



