OF THE MANAGEMENT OF LIGHT IN 

 ILLUMINATION. 



CHAPTER I. 



An Investigation of the Principles of the Art of Illu- 

 mination. — Of the Circumstances which contri- 

 bute to render Vision distinct. — Of the Dispersion 

 of Light. — Of the bad Effects of Cross- Lights. — 

 Descriptions of several new Illuminators of differ- 

 ent Forms and Dimensions. 



THE art of illumination, although it is undoubtedly 

 one of the most useful that has been invented 

 by man, and contributes perhaps more than any other 

 to his comfort and convenience in all countries and in 

 every class of society, has nevertheless been little cul- 

 tivated : it has not even been considered as an art ; for 

 the technical terms have not yet been invented which 

 are indispensably necessary in order to render it pos- 

 sible to treat of it in a clear and satisfactory manner. 



My attention was first turned to this interesting sub- 

 ject in the year 1789, when, being actively engaged in 

 the public service of the late Elector Palatine, reigning 

 Duke of Bavaria, I was employed by His Most Serene 

 Highness in establishing Houses of Industry for the 

 poor, in the cities of Manheim and Munich. In light- 

 ing up these spacious establishments, I first learned to 



