AMERICAN INSTITUTE. 597 



perfectly unbroken. At the first flashes, the zigzag sparks are 

 violet colored. As the thin stratum of water evaporates, the 

 sparks become whiter, and sometimes even bluish. When the 

 stratum of water becomes interrupted, the spark terminates in a 

 ball of lightning of a red color, so that when you wish to produce 

 ball lightning you must have the water stratum a little thicker, 

 and the varnish surface interrupted. 



ALUMINUM. 



This new metal on account of its lightness is used in decorating 

 military standards in France, making a difference of two and 

 three-quarter pounds in the weight of a standard, in tlie eagle, 

 etc., at the summit. Musical instruments are formed of it, it 

 being more sonorous than bronze, superior gongs, bells, etc. Its 

 cost, compared with silver, is in weight 300 to 225, so that an 

 article made of it of the same size would be only worth 75, while 

 its like of silver would be 225. A fork and spoon, for instance, 

 will cost 16 and the silver one 50. 



W. Y. Stewart of Glasgow, has patented moulding metals by 

 employing a core-bar on which the core surface is formed for pro- 

 ducing the interior of the pipe or hollow casting. Core bars of 

 this kind may be filled up with screw or other mechanical action 

 upon the bar themselves. 



ANNEALING CAST IRON SHAFTS AND ANCHORS. 

 S. Fisher of Birmingham, has patented this. He makes muffies 

 suited to the form of the article to be annealed; he uses fire brick. 

 This kind of mufiie will last for numerous annealings. 



DIAMONDS PRODUCED FROM CARBON. 



Mon. Despretz has been occupied a long time in studying the 

 properties of carbon, and at last resolved to try the experiment 

 of subjecting pure carbon to a very prolonged stream of the elec- 

 tricity of induction. He fixed at the positive pole of the circuit 

 occupying the lower ball of the electric egg a piece of sugar 

 candy, which, as every body knows, represents carbon in its 

 purest condition. To receive the sublimation of this carbon, he 

 adapted to the upper ball a hook of very fine platinum wire, he 

 then made as perfect a vacuum in the egg as he could, and then 

 allowed the current between the carbon and the platinum wires 

 to continue for a month. He perceived, at the end of a month, 

 that the wires were covered with a black dust, among which he 

 distinguished some crystalizations. What would be their 

 nature 1 What a question to be answered ! For, as every one 



[Am. Inst.] " 39 



