OZONE AND HYDROGEN PEROXIDE 1) ALTON'S LAW 199 



temperature, but by the employment of a continual discharge or 

 flow of electricity that is, to transform the oxygen by the action 

 of a silent discharge. 3 For this reason all ozomsers (which are of 

 most varied construction), or forms of apparatus for the preparation of 

 ozone from oxygen (or air) by the action olf electricity, now usually 

 consist of conductors (sheets of metal for instance, tinfoil or a solution 

 of sulphuric acid with chromic acid, &c.) separated by thin glass 

 surfaces placed at short distances from each other, and between which 



FIG. 37. Siemens' apparatus for preparing ozone by means of a silent discharge. 



the oxygen or air to be ozonised is introduced and subjected to the 

 action of a silent discharge. 4 Thus in Siemens' apparatus (fig. 37) the 



5 A silent discharge is such a combination of opposite statical (potential) electricities 

 as takes place (generally between large surfaces) regularly, without sparks, slowly, and 

 quietly (as in the dispersion of electricity). The discharge is only luminous in the dark ; 

 there is no observable rise of temperature, and therefore a larger amount of ozone is 

 formed. But, nevertheless, on continuing the passage of a silent discharge through 

 ozone it is destroyed. For the action to be observable a large surface is necessary, and 

 consequently a powerful source of electrical potential. For this reason the silent dis- 

 charge is best produced by a Ruhmkorff coil, as the most handy means of obtaining a 

 considerable potential of statical electricity with the employment of the comparatively 

 feeble current of a galvanic battery. 



4 V.Sabo'n (ijijifirattm was one of the first constructed for ozonising oxygen bymeanB 

 of a silent discharge (and it is still one of the best). It is composed of a number (twenty 

 and more) of long, thin capillary glass tubes closed at one end. A platinum wir- 

 tending along their whole length, is introduced into the other end of each tube, and this 

 end is then fused up round the wire, the end of which protrudes outside the tube. 

 The protruding ends of the wires are arranged alternately in two sides in such a manner 

 that on one side there are ten closed ends and ten wires. A bunch of such tubes (forty 

 should make a bunch of not more than 1 c.m. diameter) is placed in a glass tube, and 

 the ends of the wires are connected into two conductors, and are fused to the ends of the 

 surrounding tube. The discharge of a Ruhmkorff coil is passed through these cuds of 

 the wives, and the dry air or oxygen to be ozonised is passed through the tube. If 

 oxygen be passed through, ozone is obtained in large quantities, and free' from oxides of 



