Artificial Incubation. 
37 
forcing out. The pipe from the bottom compartment of the tank to the boiler is placed about an inch 
above bottom of tank ; thus there is always a la)»er of an inch or so of water, which has such a slow circula- 
tion that it acts as a sort of cushion and prevents rapid changes in heat of the bottom of tank, which is a 
great advantage. 
The diaphragm or division in the tank fits exactly, and is soldered at the boiler end and at the sides, 
and stayed top and bottom ; it converts the tank into a large pipe, and the circulation of the water is very 
perfect. The open space may be about half an inch to one inch wide. 
The flue for a 30-egg machine is 2 inches, for a 50-cgg 3 inches, and for a loo-egg machine 4 inches in 
diameter, and may be a piece of good down-piping ; it must be carefully soldered in so as not to leak, in fact 
every joint must be perfect. The tanks and boilers can be bought for from r5s. to 40s., according to size. 
Fig 31.— Detai of Regulator. 
Any intelligent tradesman could make a machine from above drawings. The capsules, which contain ether 
and alcohol, are obtainable for about 2s. 6d. each, or less. They are somewhat difficult to make. The 
evaporating-pan is same size as egg-drawer, and about an inch deep ; in the centre there is to be a hole 
2 to 4 inches in diameter, according to size of machine ; solder round the edge of the hole a ring of metal an 
inch and a quarter high. This hole then fits over the large ventilating holes in the bottom of the machine 
(Fig. 29), and on filling the pan put a piece of cheese-cloth over the hole, with its ends in the water ; then all 
the air that passes into the machine from this direction will be charged with moisture. For ventilation use a 
half-inch augur, and bore holes all round the casing just under the tank, and about 3 inches apart. Some 
amount of discretion must be exercised so as not to produce draughts in the machine. The air should come 
in from below the egg-level, and, passing through the machine, pass out of the ventilators at top. In cold 
Fig 32. -Detail of Fulcrum or Bearing. 
weather far less ventilators are required at the bottom than in hot weather. A machine similar to above, of 
amateur make, hatched 30 out of 34 eggs the first trial, and I have often hatched every egg, and always over 
90%, and get fine strong chicks. 
The sawdust packing, on top of tank should be not less than 4 inches, and at sides and end i mch, well 
rammed. 
The egg-drawers should be about 6 inches deep. If necessary to have two or more drawers the make is 
the same, making the bottoms of the drawers part of the arc of a circle, for the dishing. 
The l^est place to put an Incubator is in a well-ventilated cellar or underground room, as there is a more 
equable temperature there, and not so much vibration. However, any place that is not too exposed or 
draughty will do ; but, of course, there will be less trouble and less kerosene oil consumed if the situation be 
