138 Method of increasing Shocks, &fc. 



joints, throughout its length. The separate lengths of 55 feet are 

 cut from single sheets of copper. This is easily done by cutting the 

 alternate strips within half an inch to the edge of the sheet, and then 

 bending them one upon the other, to bring them in the same line of 

 length ; in this way the integrity of the circuit is better preserved 

 than by numerous solderings. The ribbon is wound with single 

 strips of list intervening. On five of the coils at distances indicated 

 by the figure, are soldered strips of copper which pass through the 

 cover of the box and are then bent down to receive the thimbles for 

 the mercury. This forms a convenient arrangement, as the mercury 

 cups are easily emptied by straightening the copper strips, t, rep- 

 resents the copper tube with a curved strip of copper soldered to its 

 extremity for dipping into the mercury cups. For the sake of brev- 

 ity in detailing the experiments, instead of the copper tube of right 

 or left hand, merely the words right and left hand will be used ; and 

 by the abbreviations, neg. con. and pos. con. will be understood the 

 strips of copper connecting the cups with the negative and positive 

 cups of the calorimotor. 



On putting the pos. con. into cup 1 and the neg. con. into cup 2, 

 a bright spark and sharp snap are produced, when either of the con- 

 nectors is raised from its cup. When the neg. con. is raised from 

 cup 3, the spark is more brilliant than the last, accompanied with a 

 louder snap. 



When the neg. con. is raised from cup 4, the spark is more volu- 

 minous, but not so intense as the last named, nor is the snap so loud. 



When the neg, con. is raised from cup 5, the spark is still less 

 bright, and the snap less loud. 



When the neg. con. is raised from cup 6, (220 feet,) the spark 

 and snap are both feeble, even when compared with those given by 

 cup 3. It would seem then from these results, that the limit* of in- 

 tensity is attained at cup 4, which gives a length of 110 feet; but 

 this inference is somewhat weakened by the following facts. The 

 shocks by no means obey the same law ; the maximum being obtain- 

 ed by immersing the copper tubes in cups 6 and 1. For conven- 

 ience of arrangement, suppose the positive connector is in cup 1 and 

 the right hand in cup 1. The left hand is to pass along with the 

 neg. con. into cups 2, 3, 4, 5 and 6, and as the con. is raised from 

 these cups successively, the shock increases, and from cup 6, is a 



* This limit could be more accurately ascertained by having cups on each coil. 



