RECENT DEVELOPMENTS IN THE ART OF ILLUMINATION. 
By Preston S. Minzar, 
Electrical Testing Laboratories, New York, N. Y. 
[With 3 plates.] 
In the Journal of the Franklin Institute for the last few years there 
are to be found a number of papers dealing with certain phases of 
illumination. These are of especial interest to a limited number of 
institute members, but most of them are somewhat esoteric and pre- 
sumably have been read in detail by but a limited number of institute 
members. Consideration of the character of the institute member- 
ship has led the writer to feel that he could perhaps be of some service 
by endeavoring to outline in a comprehensive way the nature and 
scope of the art of illumination and by making available a brief 
review of developments in illumination which will place before the 
members a general view of the sub- 
ject in its large features. Accord- 
ingly, this paper will be found to 
contain but little of new interest 
for the illuminating engineer, 
being written more especially for 
the consideration of the member- 
ship of the institute at large. 
In the discussion which follows 
a fragmentary bibliography is in- 
cluded. The references which are 
noted are intended to direct attention to significant papers, and to 
furnish an indication of the manner in which the several phases of 
each division of the subject of illumination are being developed. 
Illuminating engineering as a distinct specialty is perhaps not 
generally understood. The name illuminating engineering as applied 
to this specialty is perhaps not wisely chosen. It willserve, however, 
for the purpose of this discussion. Illuminating engineering, then, 
as a specialty may be represented by the diagram in figure 1. 
The specialist applies the materials of illumination with the aid of 
the science of illumination, and practices the art of illumination. 
ILLUMINATION 
MATERIALS SCIENCE 
Fic. 1. 
1 Presented at a joint meeting of the Electrical Section and the Illuminating Engineering Society, held 
Thursday, Apr. 9, 1914. (Reprinted by permission from the Journal of the Franklin Institute, October, 
1914.) 
611 
