85 



nitric, acetic, sulphurous, citric and tartaric acids. These are sur- 

 passed by the stronger mineral acids, such as sulphuric and phos- 

 phoric acid and sulphate of potash, which are again exceeded by 

 salts of potash and soda possessing either a decided acid or alkaline 

 reaction, such as binoxalate of potash, phosphate of soda and car- 

 bonates of potash and soda. The highly osmotic substances were 

 also found to act with most advantage in small proportions, pro- 

 ducing in general the largest osmose in the proportion of one-quarter 

 per cent, of salt dissolved. Osmose is eminently the phenomenon 

 of weak solutions. The same substances are likewise always che- 

 mically active bodies, and possess affinities which enable them to 

 act upon the material of the earthenware septum. Lime and alu- 

 mina were accordingly always found in solution after osmose, and 

 the corrosion of the septum appeared to be a necessary condition of 

 the flow. Septa of other materials, such as pure carbonate of lime, 

 gypsum, compressed charcoal and tanned sole-leather, although not 

 deficient in porosity, gave no osmose, apparently because they are 

 not acted upon chemically by the saline solutions. Capillarity alone 

 was manifestly insufficient to produce the liquid movement, while 

 the vis matrix appeared to be chemical action. 



The electrical endosmose of Porrett, which has lately been defined 

 with great clearness by Wiedemann, was believed to indicate the 

 possession of a peculiar chemical constitution by water, while liquid, 

 or at least the capacity to assume that constitution when polarized 

 and acting chemically upon other substances. A large but variable 

 number of atoms of water are associated together to form a liquid 

 molecule of water, of which an individual atom of oxygen stands 

 apart forming a negative or chlorous radical, while the whole remain- 

 ing atoms together are. constituted into a positive or basylous radical, 

 which last will contain an unbalanced equivalent of hydrogen giving 

 the molecule basicity, as in the great proportion of organic radicals. 

 Now it is this voluminous basylous radical that travels in the elec- 

 trical decomposition of pure water, and resolves itself into hydrogen 

 gas and water at the negative pole, causing the accumulation of water 

 observed there, while the oxygen alone proceeds in the opposite direc- 

 tion to the positive pole. Attention was also called to the fact that 

 acids, and alkalies, when in solution, are chemically combined with 

 much water of hydration, sulphuric acid for instance evolving heat 



