158 Management of Light in Illumination. 



expense ; and at the moment when they are wanted 

 they may be made to furnish their usual quantity of 

 Hght, and when they are brought back into the ante- 

 room their flames may again be reduced. They would 

 cost much less than wax tapers or bougies, and would 

 be much more cleanly and agreeable. 



As the light emitted by these lamps is exceedingly 

 vivid, and especially when they are made to burn with 

 their greatest brilliancy, their flames should always be 

 masked by screens, made of ground glass or of white 

 gauze or crape. The most simple and best form for 

 a screen for this lamp is that of a truncated cone, 6 

 inches in diameter at its base, i| inch in diameter 

 above, and 3I in perpendicular height, with a gallery 

 above, of about half an inch in height, made of tin 

 japanned, to serve instead of a handle in placing it and 

 removing it. This screen may be fixed in its place by 

 means of a conical tube of tin, attached to the screen 

 on the inside of it, which may be made to receive the 

 cone which is fixed to the stopper which closes the 

 opening by which the lamp is filled with oil. 



The handle of the lamp being six inches in length, 

 enough of it will project beyond the lower part of this 

 screen to give a sufficient hold of it in carrying the 

 lamp. 



A small balloon screen, of about six inches in diame- 

 ter, is frequently used with this lamp, and has a very 

 fine effect. This balloon is made of white crape, fixed 

 to vertical ribs of covered wire, and has an opening 

 below of about 2.4 inches in diameter, that it may rest 

 on the widest part of the circular reservoir ; and it has 

 also a circular opening above one inch and a half in 

 diameter, to give a passage to the upper end of the glass 



