896 



Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. 



Nil. HI 480 a 



61 481. 1 : 



61 480 a. 1 : 10. 



61 483. 



61,480 a. Simple Lamp Reading Apparatus, with puniffin lain]), Figure 



61.481. Lamp Reading Apparatus, for objective reading, Figure, with single filament 

 glow lamp together with switch and plug contact 



The scale is adjustable vertically and has a lateral motion with fine adjustment. A rending 

 mirror permits of a number of observers reading simultaneously without error. 



61.482. Lamp Reading Apparatus with Nernst Lamp and slot diaphragm, F i g u r e, with 

 switch, 2 metres lamp flex., plug contact and plug; for 110 220 volt 1). ('. only. . 



Lamp Reading Apparatus for fixing to Ceiling: see Nos. 61,409 and 61,410, p. 890. 



61.483. Lamp Reading Apparatus for objective reading, Figure, on wood stand, with 

 electric glow lamp and pliable Celluloid Scale, adjustable vertically 



The light from the lamp falls on a universal motion mirror. It is piojectcd thence on to 

 the mirror of the measuring instrument through a rectangular aperture acnnss which a vertical thread 

 is stretched. When the lamp reading apparatus is properly set up a strongly illuminated spot appears 

 on the transparent celluloid scale, a fine black line appearing in the centre of this spot. l.y means 

 of a screw the scale of the apparatus can be moved along its length in order to adjust the lim line 

 on the zero point of the scale. The scale can be spherically curved or stretched straight. 



61.484. -- idem, with NeriiM Lamp, for I). ('. of 110 220 volts only ">. 



61,4X.~>. -- idem, with incandescent gas burner I. 



61.486. --idem, with paraffin lamp. Figure ' 



61.487. Extra Price for a Stand for Nos. (il. is:! (iljsii lor placing on the floor. V \ g u re 1. 



61.488. Lamp Reading Apparatus, Figure, as No. t;i.is:i, but without Lamp I- 



Items Nos. 61,31061,315 can be used as Lamps for above. 



I'nlcss otherwise stated, the apparatus arc supplied with 111! volt lamps. 



Lamp Reading Apparatus Nos. 61,481 61,488 for objective reading require a Con- 

 cave Mirror on the apparatus to be read the radius of curvature of which is equal to the 

 scale distance. In all cases a Plane Mirror with projection lens can be used in front of 

 them. Suitable lenses for the individual instruments quoted on application. 



< i. iioi. 4:11--', 

 2403. 



