Miscellanies. 205 



there burst out in the southeast, at the elevation I should think of about 

 45°, a light of dazzling splendor, which rapidly spread itself around in 

 all directions, becoming less distinct, as it was further diffused. At first 

 the brightness was too intense for the eye ; and after it had lost much of 

 its brilliancy by its diffusion, it was still such as to enable me to read the 

 finest print by its light with great ease. It continued to spread around in 

 every direction, until the whole heraispbere was covered, and a beautiful 

 crown was formed in the zenith, exhibiting all the colors of the rain-bow. 

 The bursting forth of the brightness in the southeast was instantaneous, 

 and of about the apparent size of the moon. It was as if the blue con- 

 cave had been pierced through by a cannon ball, and torrents of liquid sil- 

 ver at a white heat had rushed through the aperture, rolling along in waves 

 on the inside of the shell, — gradually cooling as it spread, changing its 

 color, and becoming fixed. 



2. Transmission of Galvanic light through metals of different conduct- 

 ing powers ; by James Thomas. — On the occasion of trying some exper- 

 iments with the galvanic battery, previous to an exhibition of them before 

 the Mechanics' Institute, I wished to repeat Mr. Children's experiments, 

 relative to the transmission of the electric current through wires of differ- 

 ent conducting powers ; for this purpose I formed a chain of silver and 

 platinum wire in alternate links, and also one composed of copper and 

 platinum, following the directions given by Mr. Brande.* 



" Select some fine silver and platinum wire and cut it into lengths of 

 about two inches ; then form a continuous wire by joining these lengths 

 endways in alternate order, and suspend it in the form of a festoon, be- 

 tween two thick copper wires, forming the poles of the battery, having 

 previously temporarily united these poles by a thick copper wire ; on re- 

 moving the latter, the electricity traverses the compound wire, and occa- 

 sions the ignition of the platinum portions of it, the silver being unaf- 

 fected. The object of uniting the poles by a thick copper wire, whilst 

 the compound wire is being attached, is to prevent the sudden fusion of 

 the latter at the point of contact, which often happens when this precaution 

 is not taken." 



" Platinum and gold being thus connected and introduced into the elec- 

 tric circut, the platinum was instantly made red hot, whilst the gold re- 

 mained unaffected. With a similar arrangement of gold and silver wires 

 the gold was ignited ; the silver not. With alternations of platinum and 

 silver all the platinum wires were ignited, but none of the silver." 



On trying the experiment with a chain of this description, the battery 

 when in action was incapable of producing ignition, to any extent, in the 



* Manual, fourth edition, page 271, 



