190 Mr. A. Schuster on the Disruptive Discharge 



one part in a thousand if the distance is equal to the fifth 

 part of the radius. This accuracy is quite sufficient in the 

 reduction of any actual observations. 



For values of e/a which are smaller than '2 the last term 

 of the series may be neglected, and the equation 



maybe used; while for distances between the spheres smaller 

 than the tenth part of the radius, 



R= Ir 1+ ii-| 



e |_ oaj 



is correct for all practical requirements. For large distances 

 Table I. must be used. 



By the help of this preliminary investigation the reduction 

 of all such observations as Bailie's becomes an easy matter. 

 Table III. gives the values of R, at which the spark begins to 

 pass according to Bailie between spheres of various diameters 

 at different distances. If the so-called dielectric strength is 

 a constant these values should all be equal to each other. 



Table III. — Values of R for Spark Potential between 

 Spherical Surfaces, in Electrostatic Units. 



Explosive 







Eadius of Spheres in centimetres 



. 



distance in 



Planes. 



























centimetres. 





3 



1-5 



0-5 



0-3 



0-175 



005 

 292 



0-05 



179 



180 



186 



190 



197 



206 



o-io 



147 



149 



153 



163 



176 



198 



376 



0-15 



135 



138 



141 



157 



170 



206 



425 



0-20 



127 



131 



137 



154 



170 



219 



460 



0-25 



122 



127 



134 



154 



180 



236 



478 



0-30 



118 



124 



130 



156 



189 



253 



494 



35 



116 



122 



129 



159 



197 



263 



516 



0-40 



113 



122 



129 



164 



204 



272 



528 



045 



112 



120 



127 



166 



214 



278 



540 



0-40 



112 



118 



124 



157 



197 



268 



539 



0-45 



110 



119 



122 



167 



206 



275 



578 



050 



109 



117 



125 



166 



218 



296 



608 



0-60 



106 



116 



125 



181 



233 



327 



639 



0-70 



106 



117 



126 



188 



234 



339 



667 



0-80 



106 



123 



130 



192 



250 



349 



685 



090 



105 



120 



132 



191 



255 



349 



708 



100 



106 



128 



133 



194 



258 



349 



733 



