Management of Light in Illumination. 127 



cleaned and trimmed, and till its reservoir has been 

 filled with oil. In filling it, care must always be taken 

 to remove the three stoppers which close its three 

 openings above, in order that the air may escape out 

 of it with the greater facility, and that it may be seen 

 when it is properly filled with oil. 



As soon as the reservoir is full of oil, the openings 

 above must be closed by their stoppers, and all the 

 screws must be screwed fast, and no passage must be 

 opened for the air to enter the reservoir till after it 

 shall have been carried back and set down in its hori- 

 zontal brass hoop. 



As table illuminators are liable to be removed fre- 

 quently from place to place when they are not lighted, 

 the screw which closes the passage for the admittance 

 of air into their reservoir should not be opened till the 

 moment when they are lighted ; but as the reservoir of 

 this illuminator is not large, and as the tube is narrow 

 which conveys the oil from it to the burner, there is 

 very little danger of the oil being spilled in removing 

 it from place to place, either when it is lighted or when 

 it is not lighted, even though the passage for the air 

 should be left open. I never knew the accident to 

 happen, and it is evidently so unlikely to happen that 

 most people never give themselves the trouble to close 

 that passage on any occasion. By closing this passage 

 with a hollow, conical brass stopper, similar to that 

 used in my portable lamps which will be described 

 hereafter, the accident in question would be most 

 effectually prevented. But to return to the pendulous 

 illuminators. 



When one of these is to be lighted, the following 

 operations must be performed: — 



