470 Chronicles of Science. [July, 



substances, becomes biglily inflammable when simply moistened 

 with water. A mixture was made of 



■ 5 grammes of sodium, 

 66*0 „ nitrate of potash, 



36 "5 „ sulphide of antimony. 



Provided that during its manufacture this mixtm-e is kept thoroughly 

 dry, it has been found to answer admirably well. According to 

 several accounts from Germany, this plan of substituting sodium 

 for phosphorus has been favourably taken up by some of the largest 

 leading manufacturers of lucifer and fusee matches. There is 

 said to be not the least danger in the transport. 



It is well known that various accidents occur from fire caused 

 by persons carelessly throwing down matches, which they beheve 

 to be harmless because the flame has been extinguished, but which, 

 in reality, are highly dangerous, and quite capable of communi- 

 cating fire to any Hght dry material, in consequence of the wood- 

 splint being at a red heat, although not actually in flame. It 

 appears from the ' Scientific American ' that it has been proposed, 

 in order to prevent this, to saturate the splints, previously to their 

 being dipped, with a solution of some chemical salt which has the 

 property of preventing the wood from remaining at a red heat after 

 the flame has been extinguished without being in any way detri- 

 mental to the inflammable nature of the splint, and thus to prevent 

 the possibihty of accident from the dropping of the match after 

 the extinction of the flame, but while the sj)lint is still at a red 

 heat. The substance which it is proposed to employ is alum, 

 though other salts have the same property. The matches before 

 being dipped ai'e to be immersed in a strong solution of alum, or 

 other salt with a similar action, until they are saturated ; they 

 are then to bo di-ied and tipped with the ordinary composition. 

 Matches, so treated, are said to ignite, and burn with flame as long 

 and readily as other matches ; but the instant the flame is blown out, 

 the match becomes black and perfectly harmless. 



Electricity. — By far the most gigantic electrical instrument 

 ever made has just been fitted up at the Royal Polji;echnic Insti- 

 tution. This is the large induction-coil, which has been made by 

 Mr. Apps. It is 10 feet long and 2 feet in diameter. The core of 

 soft iron weighs 123 lbs., and consists of wires each 5 feet long and 

 • 0625 in diameter. The primary coil weighs 145 lbs., and is com- 

 posed of 3770 yards of copper wu-e. The secondary wii-e is 150 

 miles in length, and 0"015 inch in diameter. 'Jlie galvanic cur- 

 rent for the primary coil is supplied l)y 40 of Bunsen's cells. It is 

 capible of producing a spark 29 inches long, and the flash will 

 perforate plate-glass 5 inches thick. This huge and powerful coil 



