1909.] 



The Properties of Colloidal Systems. 



281 



acid. It is interesting to note that the osmotic pressure rose distinctly, 

 while the outflowing water still gave reactions with silver nitrate and with 



Fig. 2. 



a, Tube on to which the parchment-paper thimble is tied. This tube has a side branch, 

 connected by a short piece of rubber tubing to b, and thus, when the clip on tlie 

 tubing is released, the inner and outer chambers are put in connection. This is of 

 importance to control the zero point. 



c, Narrow bore tube, serving as manometer. d, Outlet tube from outer chamber. 



e, Tube conducting water from the quartz condenser,/. 



g, Flask to collect the outflowing water, apart from contact with the atmosphere. 



h, Tower containing dilute sulphuric acid. h, Soda-lime tower. 



I, Flask for boiling water. m, Trap to collect spray. n, Glass wool. 



o, Outlet for water condensed in m. 



The containing vessel is thickly coated with paraffin and kept in a thermostat. The 

 tubes a, c, d, e, and / are of quartz. 



Gunzberg's test, and, in fact, the pressure had risen to 60 mm. of water when 

 60 c.c. of the water neutralised 1*4 c.c. of decinormal ammonia. The distilled 

 water, containing carbonic acid but no basic substance, was run in at intervals 

 VOL. lxxxi. — b. x 



