II. RESEARCH. 



571 



A current of pure and dry oxygen was passed through an induction tube, 

 fundamentally of the kind devised by Siemens, but the inner tube was nearly 

 filled with water, in which was placed one of the terminal wires of Ruhm- 

 korfPs coil, the tube itself being immersed in a vessel of water connected 

 with the other terminal wire of the coil. The tube is delineated in Fig. 1: 

 The gas enters the apparatus at //, and, passing over anhydrous-phosphoric 

 acid contained in the three bulbs i, traverses the narrow space k between the 

 two tubes, and is there submitted to the electric action, after which the 

 electrized gas is again passed over anhydrous phosphoric acid contained in 

 the three bulbs /, and is delivered at m. 



Fid. i. 



The electrized gas is collected and preserved for the purpose of experiment 

 in . a gas-holder, delineated in Fig. 2. On this side of the induction tube 

 connexions of caoutchouc can no longer be employed, this substance being 

 instantaneously corroded by even the minutest trace of ozone, and the friction 

 between the gas-holder and the induction- tube is effected by means of what 

 may be termed a paraffin joint. Over the tubes to be connected, which are 

 placed close together, is slipped a piece of glass tube into which they exactly 

 fit, and from which they are separated by a capillary space ; a fragment of 

 pure paraffin is placed at the external junction of the tubes. The union of 

 the tubes is effected by gently melting the paraffin ; the liquid paraffin is 

 extremely limpid, and runs into and fills up the narrow space between the 

 tubes. When the paraffin is solidified, the tubes are united by a joint, 

 which is perfectly air-tight, which will resist very considerable pressure, and 

 which is quite unaffected by the passage of the ozone. This simple joint is 

 an essential feature of this arrangement, and will doubtless be of great 

 service in many forms of gas apparatus. 



The gas-holder consists of a glass bell p, contained in a glass cylinder q, 

 in which it is suspended, being supported by a knob of glass passing through 

 a cap fitted to the top of the jar. This cap is made in two pieces, which are 

 subsequently united so as to be readily placed in a proper position as a 

 support to the glass bell. 



At a superior level is placed a glass jar r, containing pure and concen- 

 trated sulphuric acid ; this jar is connected by a syphon tube s (in which is 

 placed a glass stop cock) with the lower cylinder q. This upper jar, which 

 I shall term the reservoir, is closed by a cap t, through which the siphon 

 tube passes, and in which is also fitted a second glass tube u. The gas from 

 the induction tube is delivered at n, whence it passes into the gas-holder by 

 an arrangement of tubes, which is best understood from the drawing. The 



