out bringing it to a boil, {Notice how they slide off 

 of the regulator question into a large tank of water} 

 which is the case where small and shallow tanks are 

 used. {A large tank of water will not cool off as 

 easily as a smaller one, and the possibility of over- 

 heating is greater and more dangerous. To produce 

 a temperature of 103 in the egg chamber the body 

 of water must be so hot ; if the temperature of Ihe 

 room rises or falls, the water in the large tank must 

 be made hotter or cooler, as the occasion demands, 

 and if a large body of water gets too hot, it stays 

 too hot longer than a smaller body of water. If it 

 gets too cold, it takes longer to reheat it. What has 

 that to do with the regulator f) 



The is supplied with FOUR exhaust 



ventilators, one at each corner of the machine, and 

 so arranged that during incubation a continuous 

 and evenly distributed current of warm air passes 

 through the egg chamber, carrying with it all gas 

 and poisonous vapor which accumulates during the 

 process of hatching, and exhausts the heat as it 

 reaches the point of 103. ( With no motive power 

 to open or close these four ventilators, will any sane 

 person imagine that they will control the temperature 

 of the egg chamber any more than four windows 

 will control the temperature of a room, unless an 

 attendant watches and opens and closes them partly 

 or entirely as the O2itside temperature changes ? On 

 the contrary, the ventilation will be greater on a 

 cold than on a warm day, the amount of air passing 

 through being governed by the changes of tempera- 

 ture of the room). By this method we have a 

 101 



T*- -T- -T, .> JE ^^s^ 



