expense, before placing the machine or contrivance 

 on the market, most persons do object to having 

 an experimental regulator palmed off on them for 

 a thoroughly tested and proven one. A mariner 

 is just as safe with a deficient compass as a poultry- 

 man is with a faulty regulator on his incubator. 

 If it occurs to you that we seem to be finding a 

 great deal of fault, we would call your attention to 

 the fact that when a surveyor makes a chart of a 

 river or bay, he does not stop at lining out the safe 

 courses and deep channels, but is equally particular 

 to designate the dangerous rocks, treacherous 

 shoals and sunken wrecks. Did we fail to do the 

 same in this line you would censure us. 



OTHER METHODS OF REGULATION. 



Take a machine with a thermostatic bar close to 

 the heater, not level with the eggs, and the bottom 

 of the incubator being nothing but one thickness 

 of galvanized iron, with water pans made in the 

 iron ; a change of temperature in the room will, 

 through this thin iron, affect the temperature of 

 the egg chamber below the thermostatic bar,' and 

 as high as the level of the egg centre, before affect- 

 ing the bar, and under some circumstances the 

 variations do not reach the bar at all. The chilling 

 of the water through this thin bottom is also fatal 

 to good results. The flame of the lamp must be 

 raised or lowered as the temperature of the room 

 changes to any extent. 



Another incubator, partly double wall, one-inch 

 112 



