Maclaukin. — PrntdtJiioiiic Acid in XatnraJ Wafers. 



11 



These results may be restated as follows :- 

 Aiiimoiiiuin-chloride (NH^Cl) 

 Potassium-chloride (KCl) 

 Sodium-chloride (NaCl) 

 Potassium-bromide (KBr) 

 Potassium-iodide 

 Sodium-sulphate (Na2S04) 

 Magnesium-sulphate ( MgSO^) 

 Calciimi-sulphate (CaSO^) 

 Alumhiium-sulphate (Al^SO^) 

 Ferric sulphate (Fe2(S04)3) . 

 Ferrous sulphate (F'eSOj 

 Manganous sulphate (MnSO^) 

 Copper-sulphate 

 Molvbdic acid 

 Silica (SiO,) 



Titanium-dioxide (TiOj) 

 Boron-trioxide (BoOg) 

 Arsenious oxide (AsoOg) 

 Carbon-dioxide (CO.") 

 Hydrochloric acid (HCl) 

 Pentathionic acid (HoSgO^) 



Per Cent. 

 00273 

 0-1654 

 0-0379 

 0-0051 

 Trace 

 0-6191 

 0-3948 

 0-5090 

 2-1090 

 0-2600 

 0-1976 

 O0038 

 Trace 

 Trace 

 0-0080 

 00030 

 0-0310 

 0-00056 

 0-0130 

 4-8338 

 0-0240 



9-24236 



The water is remarkable for its complex character, and particularly 

 ior the very large amomit of free hydrochloric acid which it contains. The 

 presence of boron is interesting, more especially as it occurs in larger amounts 

 than are found in some of the Tuscan waters used for the commercial pro- 

 duction of boric acid. 



Art. 1\. — The Conductivity of Aqueous Solutions of Carbon-dioxide prepared 

 under Pressure at various Temperatures ; with Special Reference to the 

 Formation of a Hydrate at Low Temperatures. 



By C. M. Stubbs, M.A. 



1851 Exhibition Research Scholar, Canterbury 

 College. 



Communicated by Dr. Evans. 



[Brad before the Philosophical Institute of Cantejburi/, 2nd Xovember, 1910.] 



IXTRODUCTORY. 



It is well known that at ordinary temperatures carbon-dioxide is soluble 

 in about its own volume of water, whatever be the pressure under which 

 it passes into solution, the volume of the gas being measured at this pressure. 

 Such an aqueous solution shows weak acid properties, giving, for example 

 an acid reaction M'ith phenolphthalein, and turning blue litmus purple. 

 It is assumed in text-books that a compound Ii.j,CO^ is formed which ionizes 

 as a weak acid into H+ and HCO.,~. 



