Electrical products -Calcturti Gacbifce. 229 



The process of manufacturing calcium car- 

 bide is as follows: Ordinary lime before it is 

 slacked is ground to a fine powder; then it is 

 mixed with powdered coke or carbon in the 

 proper quantities, so that when a chemical 

 union takes place the proportion will be as be- 

 fore stated, one atom of calcium to two of car- 

 bon. As is well known, lime is procured by 

 exposing ordinary limestone to a red heat for 

 some hours together. The heat disengages the 

 carbon dioxide, leaving only a combination of 

 calcium and oxygen, which is common lime. 



The mixture of ground lime and coke is put 

 into a crucible that surrounds the arc of an 

 eleetric light of enormous dimensions; the car- 

 bon conductors amounting to an area of one 

 square foot or more. In order to cause the car- 

 IM.M t( unite with the calcium a very intense 

 heat is n -quired, such a heat as can be obtained 

 '.nly in the arc of an electric light. When the 

 enormous current is turned on (amounting to 

 .vi-r '5000 horse-power) the mixture is melted, 

 SUM] after an exposure to this intense heat for 

 ran length of time the oxygen of the un- 

 slacked lime is thrown off and the carbon 

 unites with the ealeiuni. which remains in the 

 rtions of one ;it<>in of calcium to two of 

 carbon. ;i- before Mated. Tins, it will be noted, 

 i- purely a heat process, and ;m intense one at 

 that. Xi elect rolytie action beintr required, 

 the alternating current is used without trans- 



