On the W aters of the Salt Lake of Urmi. 



317 



Or, recalculated for 100 parts by weight of total salts, we have — 



Chlorine (CI) 



Sulphates (S0 3 ) 



A. 



B. 





57-315 



4-189 



4-238 



0-407 



0-474 



4-229 



4-207 



0-941 



0-941 



45-822 



45-753 



- 12-939 



-12-931 



100-000 



99-997 



The hypothetical proximate composition of 100 parts of the total 

 salts was calculated, with the following results : — 



A. 







r 



i. 



N 



ii. 



Sodium chloride 



86-332 



86-203 



86-203 



Magnesium chloride 



6-661 



6-816 



6-816 



„ sulphate . . . 



4-211 



4-150 



3-915 



Calcium sulphate 



0-988 



1-151 



1-151 



Potassium sulphate 



1-741 



1-741 



1-741 





99-933 



100-061 



99-826 



Result B i was obtained by calculating the magnesium sulphate 

 from the residual sulphate (S0 3 ). Result B ii from the residual mag- 

 nesium. 



It is a remarkable fact that notwithstanding the occurrence of lime- 

 stone rocks and pebble beaches in the lake, no combined carbonic acid 

 could be detected in the water ; indeed, there would be no base for it 

 to combine with. On the other hand, small quantities of free carbon 

 dioxide were present dissolved in the water, and were estimated by 

 Tornoe's method.* 



A. B. 

 Free carbon dioxide in solution... 0'028 per cent. 0-017 per cent. 



Result A was the mean of two determinations which agreed to 

 within 0-002 per cent., and result B was obtained twice by the use of 

 different standard solutions ; the results were identical. 



* Before applying Tornoe's method for the estimation of carbon dioxide to the 

 samples of water A and B, two determinations of combined carbon dioxide in a 

 dilute and standard solution of sodium carbonate were carried out, in order to 

 ascertain the degree of accuracy one might hope for. In the first, the carbon dioxide 

 found only exceeded that known to be present by 0*0003 gram, and in the second 

 by 0-0001 gram. 



