PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 935 



Expansion Due to the Galvanic Current. 

 Mr. E. Edlund, of the Swedish Academy, has made a series of 

 experiments with conductors of a galvanic current to ascertain 

 whether the expansion they undergo is simply the result of their 

 increased temperature, or whether it is gi-eater. He invariably 

 found the expansion of his conductors (platinum, iron and brass) 

 was greater than would be produced by the actual heating of 

 these metals to the temperature indicated. This increased effect 

 he proposes to call galvanic expansion, to distinguish it from 

 calorific expansion. The galvanic expansion increased rapidly 

 with the intensity of the current ; but the ratio of expansion and 

 intensity he has not yet determined. 



Oreide. 

 This allo}^, resembling gold in color, is now manufactured at 

 Waterbury, Conn., by mixing pure copper, 100 parts ; zinc or 

 (preferably) tin, 17 parts ; magnesia, 6 parts ; sal ammonia, 3-6 

 parts ; quicklime, | parts ; tartar of commerce, 9 parts. The 

 copper is first melted, then the lime, magnesia, sal ammoniac and 

 tartar are added, little at a time, and the whole is briskly stirred 

 for about a half an hour so as to thoroughly mix the whole ; then 

 the zinc or tin is added in small grains, and the mixing process is 

 continued. Finally the crucible is covered and the fusion is kept 

 up for about thirty-five minutes. After the dross is skimmed off 

 the brass is ready for use. It is quite malleable and ductile, being 

 distinguishable from gold only by its inferior weight. 



A New Glowworm. 

 William Perkins, Esq., of the Koyal Geographical Society of 

 London, Avrites from Rosario, Argentine Eepublic, that in the 

 Grand Chaco, he had found the most extraordinary elateride ever 

 heard of. It is a most brilliant glowworm, one inch and a half 

 long, with two fires. The body emits a most vivid light, of 

 the ordinary greenish phosphorescent color, while the head pre- 

 sents the appearance of a bright, glowing, red, coal of fire. The 

 reflection on a piece of paper is also of two colors. He had never 

 seen anything so beautiful. Mr. Bollaert, a member of the same 

 society, says this is, doubtless, one of the cocuyos family. He had 

 noticed glowworms in the West Indies, North and South America, 

 but never in such abundance and beauty as in the wilds of West, 

 ern Texas ; still, he never ol)served but one light, the green. 



