THE INCUBATOR 47 



23. Push the lead weight quite to the left. 



24. Turn the milled head-screw P until the damper P 

 rests on the chimney V. 



25. Drop the thermometer gently down the tube pre- 

 pared to receive it, and see that the whole of the bulb and 

 a little of the stem is visible inside. 



26. Shut the doors of the iacubator. 



27. Fill the lamp with good American petroleum oil, and 

 trim the wick so that when burning it shall produce a flame 

 without tails. 



28. EefiU the lamp every twenty -four hours, and trim the 

 wick as required. 



29. Light the lamp, put on the chimney, and turn the 

 flame low to prevent smoke. 



30. To put the lamp into the lantern, pass your fore- 

 finger through the looped handle, and press the thumb- 

 piece as far down as it will go. Slide the lamp into the 

 lantern, release the thumbpiece, and you will now find 

 that the chimney touches the horizontal plate in the 

 lantern, and so establishes a direct communication between 

 the lamp-burner and the flue. If the communication is 

 complete, the oil good, and the lamp properly trimmed, 

 there will be no smell whatever. 



31. Turn the flame to about half the height at which it 

 will burn without smoking. 



82. The incubator may now be left for an hour, but 

 before doing so the present temperature should be noted. 

 On your return observe whether the temperature has risen, 

 and if not, raise the lamp-flame a little. 



33. The flame must always be somewhat in excess of that 

 required to keep up the temperature. If you exceed the 

 required amount considerably it is of no consequence, as 

 the apparatus will get rid of it ; but you will be burning 

 more oil than is necessary. 



