Not many ages ago, glass windows were unknown 
luxuries. With light control by glass came also a means of 
controlling the regularity of domestic routine, and steady 
application to crafts and trade without regard to cold or rain. 
The world was put in a frame. With electric light not only can 
we carry out the most precise operations with no regard for 
time or place or climate, but we can photograph the 
submicroscopic as easily as we can enter the subterranean 
world of the mine and of the cave-painters.

     Lighting as an extension of our powers affords the 
clearest-cut example of how such extensions alter our 
perceptions. If people are inclined to doubt whether the wheel 
or typography or the plane could change our habits of sense 
perception, their doubts end with electric lighting. In this 
domain, the medium is the message, and when the light is on