186 BULLETIN 139^ UNITED STATES NATIONAL MUSEUM 



compelled by their environment and the character of the fuel to use 

 an open lamp. 



The various interactions of environment, fuel, etc., as in the case 

 cited, often give rise to forms of extreme primitiveness in the midst 

 of inventions which evidence a high civilization. As a historical 

 fact the tropical and subtropical lamps were simple and undifferenti- 

 ated because there was very little need for artificial light, since the 

 uniform day and starht night, together with the simple habits of the 

 people, rendered better means unnecessary and accordingly not 

 liable to appear under these repressive influences. 



The broad periods of day and night with shadings of twilight form 

 the natural optic environment in which man is planted as a part of 

 animate life. The natural state of existence which is assigned to 

 early man enforced upon him a general uniformity. The activities 

 of vegetation are for the most part diurnal; of animal life diversified, 

 that is, relegated to night and day according to specific habits. Man 

 being in growth uniform with the animal kingdom, was in his ac- 

 tivities primarily a day animal, providing for himself a place for rest 

 at night and not roving abroad for nocturnal adventure. The nor- 

 mal life of tribes in a low state of progress seems to bear out the 

 latter generalization. 



The change in habits brought about in the human species through 

 the adoption of fire and thence in some degree the use of artificial 

 light has a speculative interest. That a change took place, however 

 rudimentary at the outset, is undoubted. It is easily imagined, even 

 logically to be advanced, that the earliest appreciation of fire was 

 psychological, its brilliancy at night in contrast with its eclipse dur- 

 ing dayhght being most marked and giving a sense of comfort and 

 rehance. In no sense were the utilities of fire comprehended. It is 

 possible that the ancestors first took up fire as they would a bright 

 stone, feather, or anything else that might excite the curiosity. 



Naturally, there was other experiences connected with the capture 

 of fire that are not necessary to be discussed here. 



The utilities that followed the possession of fire, however, are 

 within the province of safe speculation. Of these uses the first is 

 light, which thenceforward from the smaU beginnings would produce 

 increasingly changes in the habits of man. The consideration of 

 light as a civilizing agent of importance would touch upon the ad- 

 vances in the science of illumination, using the steps as an index of 

 man's progress in culture. We may now in this age sum up the 

 benefits that light has conferred upon civilization and may prophesy 

 concerning the developments with which the future is burdened. 



Before sketching the salient features of the subject it may be men- 

 tioned that the attractiveness of light for many species of animals is 

 a matter of common observation, and it is also known that many 



