ELECTRIC DISCHARGE WITH THE CHLORIDE OP SILVER BATTERY. 
79 
were again laid down on these new curves, and it will be seen from tig. 76 that they 
do not differ more from the experimental results than the experimental numbers from 
each other. 
On the diagram the results for each series are distinguished by no dot, one dot or 
two dots on the crosses marking the position of the observations (fig. 77). It would 
appear, therefore, that the hyperbola fairly represents the law of discharge between 
planes.* 
and the difference of these reciprocals obtained; the reciprocal of this difference gives the distance VC 
the semi-axis major =a, C being the centre; the ordinates ij, y l ... y 15 .., are obtained by the formula 
b v/ (x+a)(x—a) 
a 
the value of b=Cb, the semi-axis minor, is calculated from the measured ordinate y for both the points 
of intersection g' and h' of the experimental curve and the proposed hyperbola, and their mean taken for 
the value of b. 
b= ya -. 
x/ (x + a) (x — a ) 
The calculations are simplified by taking 2 a= V V' and adding it to Vy to give =x + a=x, taking Vy as 
=x—a=(3 and making - =c, the formula then is y= -/aft . c. 
Fig. 75“. 
Dr. Alexander Macfarlane has published in the Transactions of the Royal Society of Edinburgh, 
1878, vol. xxvii., an elaborate and careful research of the “ Disruptive Discharge of Electricity ” in air 
and different gases, and between terminals of various forms. An abstract of this paper will be found in 
‘ Nature,’ December 26,1878, pp. 184, 185. Dr. Macfarlane used a Holtz machine and employed higher 
potentials than those used by us; he found that the results for the discharge between two discs 4 inches in 
diameter at various distances up to 1'2 centims and with various pressures were satisfactorily represented 
by the hyperbola. 
