508 



Mr. E. 0. Rimington on Luminous 



On approaching to the bulb, ring becomes 



connected, 

 brighter. 



On approaching D less bright. 



If arranged as Expt. 1, case (2), the reverse happens. 



All the above four experiments give the same effects if the 

 turn of wire be larger than the bulb, as in fig. 3, only a longer 

 spark-gap has to be used. 



Expt. 5. — A single turn of 

 wire (fig. 3), a b, larger than 

 the bulb is employed, and between 

 the bulb and the ring a semicir- 

 cular strip of tinfoil or metal T is 

 placed. The wire is connected as 

 in Expt. 1. The spark-gap is 

 arranged to give no ring. Con- 



Fig. 3. 



necting T to B bright ring, T 

 to A no ring. The reverse hap- 

 pens if the tinfoil is placed in 

 position T' as shown by the dotted 

 line. 



Expt. 6. — A piece of gutta- 

 percha covered wire is bent into 



shapes shown in figs. 4 and 5. On placing either of these 

 over bulb as in fig. 6, a figure of eight-shaped luminous 



Fig. 4. 



discharge is obtained, and there is no noticeable difference 

 between the two. 



a c 



Expt. 7. — Putting the wire (fig. 4) on bulb as in fig. 7, a 



