SPECIFIC CtRAVITY AND DISPLACEMENT OF SOME SALINE SOLUTIONS. 151 



compression accompanying the act is less in both cases. When 1/256 NaCl has been 

 dissolved in 1000 grams of water the increment of displacement per gram -molecule, 

 v/m, is 24"832, and when 1/512 NaCl has been dissolved in 1000 grams of water the value 

 of vfm, is 28*672, which is greater than that of the salt in crystal, namely, 27 "209. 



§ 72. Experiments on Solutions forming Arithmetic Series. — Two sets of such 

 experiments were made, the first series having the common difference 1/128 gram- 

 molecule, while the other had a common diff"erence 1/64. 



The method of preparation of the solutions has been referred to in § 68, and in 

 this connection it is only necessary to say that, owing to the interesting nature of 

 the results obtained, it was considered advisable to repeat the experiments on certain 

 solutions in order to check the results obtained. 



In each of these cases the solution was prepared by the direct dissolution of the 

 salt in water. 



The result of these repetitions was in all cases to confirm the results obtained in 

 the original experiments, and will be referred to later. 



§73. Series of Experiments on Solutions having the Common Difference dm= 1/128. 



NaCl = 58-5. T= 19-50° C. 



m. W. 



s. 



A. 



dA. 



d log A. 



d log A 



dm 



rfA 

 dm' 



V 



m 



8/128 

 7/128 

 6/128 

 5/128 

 4/128 

 3/128 

 2/128 

 1/128 



1003-656 

 1003-199 

 1002-742 

 1002-285 

 1001-828 

 1001-371 

 1000-914 

 1000-457 



1-002636 

 1-002294 

 1-001947 

 1001615 

 1-001295 

 1001007 

 1-000652 

 1-000325 



1001-017 

 1000-903 

 1000-793 

 1000-669 

 1000-530 

 1000-364 

 1000-262 

 1000-132 



0-114 

 0-110 

 0-124 

 0-139 

 0-166 

 0-102 

 0-130 



0-0000492 

 0-0000475 

 0-0000540 

 0-0000592 

 0-0000738 

 0-0000437 

 0-0000564 



0-0062976 

 0-0060800 

 00069120 

 0-0075776 

 0-0094464 

 0-0055936 

 00072192 



14-592 



14-080 

 15-872 

 17-792 

 21-248 

 13-056 

 16-640 



16-272 

 16-512 

 16-917 

 17-126 

 16-960 

 15-531 

 16-768 

 16-897 



. § 74. Difference of Displacement, dA. — The numbers in the column dA show a 



characteristic rise in value from 7/128 to 3/128 gram-molecule concentration, and then 



a fall at 2/128 gram-molecule. 



dA 

 Under ^ — these differences are referred to the constant value m=l and reproduce 



am ^ 



in an exaggerated degree the rise from the 6/128 to 3/128 gram-molecule. 



The values for v/m show a similar rise, but the maximum occurs at the value for m 



dA 

 immediately preceding that for the maximum value for -^ — , but the character of the 



change is the same. 



The following table, which gives the maximum, mean, and minimum specific 

 gravities for each value of m, together with the corresponding values for displacement 

 and the difference of displacement for successive maximum, mean, and minimum 

 displacements, confirms the reality of the character of change in the values for d/1 : — 



