76 Kaunas Acadcmij of Science. 



MUNICIPAL ILLUMINATION. 



I'.y .1. A. (i. Shirk. 



BEFORE the days of systematic street lighting only those 

 ventured out at night who had urgent business or ample 

 bodyguard. The committing of crime under cover of darkness 

 was what drove our grandfathers to devise their crude systems 

 of street illumination. City streets have become safe just to 

 the extent that they have become well lighted. It is true that 

 light alone would be insufficient protection, but it is equally 

 true that police alone, in reasonable numbers, can not afford 

 complete protection. A city in these days can certainly afford, 

 and the citizens reasonably expect, to have the fullest possible 

 degree of protection every hour of the day. Thus the first 

 reason for instituting street lights is still one of the main 

 factors in determining the nature and amount of municipal 

 illumination. 



Closely associated with the reduction of the amount of crime 

 is the prerention of accidents to those who use our walks and 

 streets at night. We all know how a small object on the walk, 

 or some defect in it, may become a menace to our safety when 

 there is insufficient illumination. Vehicles which travel rap- 

 idly carry their own special means of lighting the road, but it 

 is unnecessary that pedestrians carry with them a lantern as 

 in the earlier days of our national history. And all cities are 

 striving to make the passage of their walks more convenient 

 and pleasant, as well as safe, by introducing a well-distributed 

 system of illumination. 



For this purpose to-day there is nothing superior in point 

 of cost and service to the new nitrogen-filled tungsten lamps 

 installed on pole brackets with good reflectors. These lamps 

 have the short, rugged filament characteristic of all series 

 lamps, and have an efficiency of about .6 watt per candle- 

 power, in comparison with the form still used in many installa- 

 tions of the longer and finer filament of the multiple lamps, 

 giving only about half as much light for the same amount of 

 electrical energy consumed. 



In some cities there is still in use the old, glaring arc lamps 

 placed at the street intersections, and often, on account of 



