HOW TO TELL A FRESH E(!G. 269 



ingenious machines is simple. The eggs are first, 

 of course, selected with due care. An easy 

 method of ascertaining their freshness, is by exa- 

 mining the size of the air receptacle at the large 

 end ; this is done by means of a hole in the wall of 

 a darkened room. On the broad end of an egg 

 being placed against this aperture, the light which 

 streams in through it reveals a certain black space 

 corresponding to the air-receptacle within. It 

 has already been said that the longer the period 

 that has elapsed since the egg was laid, the larger 

 this air-receptacle becomes. A simple means of 

 ascertaining its comparative freshness is thus ob- 

 tained. Our housewives are in the habit of getting 

 similar information by holding the egg to the light, 

 in such a manner as to show the size of the air- 

 receptacle. The renowned M. Soyer says: "The 

 safest way to try eggs is to hold them to the light, 

 forming a focus with your hand ; should the shell 

 be covered with small dark spots, they are very 

 doubtful, and should be broken separately in a 

 cup, and each egg smelt previously to using them. 

 If, however, in looking at them, you see no trans- 

 parency in the shells, you may be sure they are 

 rotten, and only fit to be thrown away. The most 



