242 



DE. A. MATTHIESSEN 0]V THE EXPANSION 



as it was carefully distilled, but those who have tried to prepare absolutely chemically 

 pure water know how difficult it is to prepare it in such a state, that it does not on evapo- 

 ration leave a slight residue. 



From Kremer's experiments on the expansion of solutions of salts in water, it appears 

 that even large percentages have only a slight influence on the coefficients of expansion 

 of the water in which they are dissolved. Table VIII. contains some examples. 



(1) Expansion of water between 19°-5 and 100°*.' 



(2) Expansion of water containing in 100 parts 5-2 parts of chloride of potassium t. 



(3) „ „ „ „ 4' 7 „ chloride of sodium f. 



(4) „ „ „ „ 7-5 „ sulphate of sodium*. 



(5) „ „ „ „ 5'1 „ sulphate of potassium*. 



(6) Expansion of water, calculated from the above fonnulce, taking the volume at 19-5, equal to 1-00000. 



For the series contained in Table IX. common water was used. Water from the 

 laboratory tap was well boiled to precipitate the carbonates held in solution by the free 

 carbonic acid, filtered and mixed with 25 per cent, of distilled water, to prevent any 

 precipitation of salt on boiling to drive out the absorbed air; in fact these 25 per cent, 

 were added to replace the loss by evaporation. The determinations with this water were 

 carried out in the usual manner; the piece of glass employed was the same as that used 

 lor Series 3. 



Table IX. 



The calculated volumes have been deduced from the above formulae ; the obsei-ved 

 value in the second column at 20°-7 being taken equal the calculated one in order to 

 compare the other two values with those obtained from the experiments made with pure 

 water. 



For the convenience of experimenters, I give in Table X. the volume occupied by 

 water from degree to degree, taking that at 4:°=l-000000, as well as the differences for 

 each degree. 



* PoGG. Ann. cxiv. 41. t ^d. c. 394. 



