1 30 Management of Light in Illumination. 



appearance. These branches are three-cornered tubes, 

 having one of their flat sides uppermost. 



The openings by which the air enters the burner are 

 distinctly seen just above the level of the projecting 

 rim of the column ; and just above these openings the 

 projecting edge of the vertical wheel is seen, which is 

 turned round in lowering or raising the wick. 



Just above this wheel is a moulding; but the illu- 

 minator would have a more simple and more elegant 

 appearance if, by lowering the moulding to the level of 

 the wheel, this might appear to make a part of the 

 moulding. 



The openings for the admission of the oil and for 

 the passage of the air in and out of the reservoir are 

 not represented in this figure. The foot on which 

 the column is placed is 5.4 inches square and 1.5 inch 

 thick. It is usually painted and japanned so as to 

 resemble a piece of marble or granite. 



On this square foot the plinth of the column is fixed, 

 which is 3.35 inches square and 0.4 of an inch thick; 

 and on the plinth the column is placed,, which is orna- 

 mented with mouldings, and often gilded and japanned. 

 It is 1.88 inches in diameter above and 2.1 inches in 

 diameter below,' and at its upper extremity it has a rim 

 which projects outwards 0.4 of an inch. This rim is 

 very useful in transporting the illuminator from place 

 to place, as it affords a firm support for the hand. 



The column is made of strong tin ; and it is closed 

 below, that it may the more conveniently serve as a 

 reservoir for the oil which may occasionally leak out of 

 the burner. 



The burner, properly so called, is a cylinder of tin, 

 3.8 inches in length and 1.05 inch in diameter, con- 



