417 



corks, fitliiig exactly in the wider tubes w and z (open at the 

 bottom) and are fille(i with some mercury. B_y means of a resistance 

 IOC (lie intensity of the current can I bus be regulated, that the 

 amount of the electrolysis can reach the desired extent. Thus it is 

 possible to keep the oxygen-development, occurring in the tube z 

 at the electrode /j,, in balance with the (), -consumption of the 

 respiration. As a resistance {we) a glass basin with water, in which 

 the electrodes iv^ and ;,, is quite satisfactory for this purpose. By 

 moving w,, which is fastened to a stand, along a sloping board, 

 not only the distance ?«, — Cj is made smaller or larger, but this 

 electrode also goes more or less deep in the water. 



The Oj formed in c is in ()[)en connection with the manometer 

 ?«, and the respiratory-vessel. The tube z really is likewise a mano- 

 meter, in which the lye will be equally higii as in c, when the 

 quantity of 0, developed is equal to the (piantily disappearing in 

 the apparatus; ?/i, however, as already mentioned, is necessai'y to 

 control the ozon-formation. 



For receiving the hydrogen, formed at the electrode /», in the 

 tube IÜ, the burette bii serves, which gives accurate readings to 

 0.1 cc. This burette ends at the top in a Itent glass tube 3, provided 

 with a glass cock k. At the bottom the burette has a narrow 

 aperture, while not fai' fi'om this a lateral tube has been fitted on, 

 forming a connection with I he tube lo. When the burette is placed 

 in such a way, that the l)Oltom aperture lies just below the water- 

 level in the thermostat, it is impossible, that while water is flowing 

 out, air is ascending in the burette at the same lime. Filling the 

 burette with water from the thermostat is done by closing /(,,, 

 opening /: and sucking at the lube 3. When after tilling k is closed 

 and k^ open, the only reason why waler should flow from the burette, 

 is the formation of hyiirogen in ir, which rises in the full burette 

 as bubbles. The formation of the first liydrogen-bul)bles in the burette 

 requires a little effective pressure, which is shown by the fall of 

 the fluid in the tube iv. This efteclive pressure, which remains 

 constant during the em|)lying of the burette, should exist before the 

 observations begin, lest the first reading should give a too small 

 figure. Tliis error is prevented, when some minutes before the 

 experiment commences — when the apparatus still works ventilating — 

 the electrolysis is made to take place, till the first bubbles rise in 

 the burette. In case that, during one and the same observation, the 

 burette is filled several times, the sucking up of the water should 

 occur very slowly and equally, lest the hydrogen, which is in the 

 connective-tube between l\ and the burette, should be sucked in 



