io6 Management of Light in Illumination. 



candles must necessarily fatigue them very much, and 

 render it impossible to see distinctly any objects that 

 may happen to be near those dazzling sources of 

 brightness. A near view of the naked flame of an 

 Argand lamp is quite insupportable, as is well known ; 

 but the advantages which would result from masking 

 those flames, and all others used in domestic illumina- 

 tion, have never been justly estimated. That subject 

 has never been properly investigated. 



The only way in which the flames of lamps and can- 

 dles can be masked, without occasioning a great loss of 

 light, is to cover them by screens composed of such 

 substances as disperse the light without destroying it. 

 Ground glass, thin white silk stuffs, such as gauze and 

 crape, fine white paper, horn, and various other sub- 

 stances, may be used for that purpose, and have been 

 used very often. 



This contrivance has been in use several years, in 

 most parts of Europe, for moderating the too powerful 

 brightness of Argand's beautiful lamp ; but so many 

 important advantages would be derived from the gen- 

 eral use of it in all cases, and it would give rise to so 

 many elegant improvements in the forms of illumina- 

 tors, that too much pains cannot be taken to recom- 

 mend it. 



This system of illumination has been universally 

 practised by the Chinese for many ages ; and so wise 

 and so economical a nation could not have continued 

 to practise it so long, had it not been found to be really 

 advantageous. But, without depending on this author- 

 ity, the utility of the system can be demonstrated by 

 direct and decisive experiments. 



As there can be no difference of opinion respecting 



