EGGS IN COLD STORAGE. 55 



summer months, also during* a large portion of the 

 spring- and fall months, unless cooled and purified 

 first. The fact that we cannot see the moisture de- 

 posited in the form of beads of water, or floating- in 

 the air in the form of fog- or mist, does not indicate 

 that it is not present. The sling- psychrometer, de- 

 scribed in discussing- humidity, will give an accurate 

 indication of the result of this unscientific method of 

 ventilating-. 



Any natural means of handling- air for ventilation *}Jf Bri ** s 

 is inaccurate and inoperative, or it may be positively ventllatlon - 

 harmful, except under favorable conditions. If de- 

 pending- on natural gravity for ventilation it will be 

 g-uesswork, to a greater or less extent, because de- 

 pending on conditions which vary with the season, 

 temperature, direction and force of the wind, etc. 

 The late Robert Brig-g-s, an authority on ventilation, 

 makes a concise statement of the advantages of using 

 fans for ventilation, in his " Notes on Ventilating and 

 Heating."* He says: "It will not be attempted at 

 this time to argue fully the advantages of the method 

 of supplying air for ventilation by impulse through 

 mechanical means the superiority of forced ventila- 

 tion, as it is called. This mooted question will be 

 found to have been discussed, argued and combated 

 on all sides in numerous publications, but the con- 

 clusion of all is, that if air is wanted in any particular 

 place, at any particular time, it must be put there, 

 not allowed to go. Other methods will give results 

 at certain times or seasons, or under certain con- 

 ditions. One method will work perfectly with certain 

 differences of internal and external temperature, 

 while another method succeeds only when other 

 differences exist. . . . No other method than 

 that of impelling air by direct means, with a fan, is 

 equally independent of accidental natural conditions, 

 equally efficient for a desired result, or equally 



* Proc. Am. Soc. Civil Engineers, May, 1881. 



