108 



FIRST LESSONS IN POULTRY KEEPING. 



liy au illustration from sitnateur photography with which many readers are somewhat familiar. 

 The photographer cau purchase a little book containiDi? carefully worked out tables which 

 enable him to determine In a momentjust what time to give an exposure with the diaphragm 

 of any given dimensions and with any possible combination of li^ht and surrounding objects. 

 By the useof such tables thephotographer reinforces and regulates hisjudgmeut, and is enabled 

 to eliminate from his work much of the risk of spoiling plates or films and losing much desired 

 pictures. So in the development of artificial incubation we are evidently coming to a time 

 when the operator will be given more appliances to record conditions he has to reckon with, 

 ju>t as the thermometer now records the temperature; and will be furnished tabulated instruc- 

 tions as to the adjustment of the machine to conditions. 



Jleantime the amateur incubator operator need not be discouraged because in the operation 

 of incubators he must rely much on his own judgment. At this stage of affairs he may get as 

 good results as others by simply l)eing sure he is on the safe side. 



I went one day to see the new incubator cellar on a large duck plant in this state. It was 



One of Farrer Bros,^ Brooder Houses^ W. Norwell^ Mass. 



■built something like that in the illustration, but with the walls high enough above ground to let 

 In full half windows on the sides, while the roof was high in the middle. As you entered the 

 door and looked about the effect was much like that of an empty church. In a church or any 

 other building for large gatherings the walls must be high that there may be in the room a 

 volume-of air great enough to move and create the necessary ventilation without great change 

 of temperature. The builders of this inculiator cellar had the wime end in view. There was 

 room enough in the building for a cellar higher than usually used for incubators and for a very 

 large loft over it. There wus so much room that my firs-t que^tion was as to whether they had 

 completed the building, or intended to make a loft. Tlie reply was that the building was to be 

 used as it was ; that it had been planned to give abundance of air to the machines. I noticed no 

 odor from the lamps and machines in that cellar. 1 have gone into many Incubator cellars In 

 which the odor waj very bad. In some of these this was because ventilation was defective 

 regardless of the number of machines in operation ; in others it was because entirely too many 

 iiiiiibators were in operation In the room. 



