470 



Propagation and Intensity of Light. 



No. 5365(5 



53657. 1:16. 



53.656. Glow Lamp Photometer, Figure, with comparison apparatus on Joly's principle, d. 

 which permits of very sharp focussing 7. 10. 



The photometer is 1 m long and is arranged in such manner that the candle powers of glow- 

 lamps can be compared without a dark room, the ratio of intensity being read direct on a scale. The 

 range extends in" both directions from 1 to 10 times. The exchange of the glow lamps under test 

 proceeds very rapidly. Calibrated glow lamps are used as standards. The apparatus is fitted with 

 Edison Glow lamps sockets, but can be arranged for any other holder. 



Comparison Glow Lamps see Nos. 53,660 53,662. 



53.657. Large Photometer Bench, 3 m long, Figure, with millimetre graduation, 3 Stands 

 on Carriage, fitted with Lummer-Brodhun Photometer Head, Hefner Lamp, Candle 

 Holder, Lamp Table, Photometry Stand for glow lamps and a Mirror for determining the 

 luminous intensity of arc lamps at various angles of emission 34. 0. 



The photometer bench should be placed on a table of suitable height so that the graduations 

 can be conveniently read off: see also No. 53,659. 



53.658. Angle Mirror for photometering glow lamps in accordance with the Rules of the Verband Deutscher 

 Elektrotechniker 1. Hi. n 



53.659. Portable Iron Table for the large Photometer Bench No. 53,657, with Rotary Switch- 

 board and Regulating Resistance, Figure. Price exclusive of measuring instruments, 

 regulating resistance, and photometer bench 17. 0. 



The switchboard carries 1 voltmeter, 1 ammeter, and 1 wattmeter, also the requisite plug- 

 contacts. The regulating resistance can also be manipulated from the farthest end of the bench. The 

 prices of the measuring instruments and regulating resistance vary according to local current and 

 voltage conditions, as to which we should require precise details. 



This table used in conjunction with photometer Bench No. 53,657 is intended for testing the 

 luminous intensity of glow lamps in factories and electricity works. 



53 ; 660. Glow Lamp for use as Comparison Lamp, of appmx. 5, 8, 10, 16, 25, and 32 Candles 

 (Hefner), specially for photometering glow lamps with Apparatus No. 53,656, for an 

 accurately prescribed voltage 0. 5. 



These comparison glow lamps are supplied calibrated at an accurately prescibed voltage and for 

 a luminous intensity in one direction, approximately as ordered, e. g. for 16.6 Standard Candles (Hefner) 

 at 110 volts. 



The lamps are supplied for the usual voltage-: when ordering the Voltage available and desired 

 candle-power should be stated; in every case only one of these two values can be strictly adhered to. 





Zinc-Bulb Photometer for Determining the ultra-viole 

 Radiation of the Sun quoted for on application. 



C'l. 6039, 1217. 



