150 



MR J. Y. BUCHANAN ON THE 



The second series of experiments was made on a series of solutions having a common 

 difference of 1/64 gram-molecule. In this series it was necessary only to make experi- 

 ments on solutions where ?w = 5/64, 6/64, 7/64, 8/64, as the first four solutions were 

 included in the first arithmetic series. 



The remaining solutions necessary to complete the geometric series from 1 to 1/512 

 gram-molecule were prepared in each case by the direct dissolution of salt in water. 



§ 69. Experimental Results. — The following table, abstracted from the full table, 

 § 67, gives the experimental results for the geometric series from 1 to 1/512 gram- 

 molecule solutions : — 



NaCl=58-5. T = 19-5°C. 















d log A 



dA 



V 



m. 



W. 



s. 



A. 



dA. 



d log A. 



dm 



dm 



m 



1 



1058-500 



1-039683 



1018-099 











18-099 



1/2 



1029-250 



1-020283 



1008-789 



9-310 



0-0039897 



0-0079794 



18-620 



17-578 



1/4 



1014-625 



1-01U300 



1004-281 



4-508 



0-0019450 



0-0077800 



18-032 



17-124 1 



1/8 



1007-312 



1-005166 



1002-135 



2-146 



0-0009290 



0-0074320 



17-168 



17-080 1 



1/16 



1003-656 



1-002636 



1001-017 



1-118 



0-0004851 



0-0077616 



17-888 



16-272 



1/32 



1001-828 



1-001295 



1000-530 



0-487 



0-0002099 



00067168 



15-584 



16-960 



1/64 



1000-914 



1-000652 



1000-262 



0-268 



0-0001175 



0-0075200 



17-152 



16-768 



1/128 



1000457 



1-000325 



1000-132 



0-130 



0-0000564 



00072192 



16-640 



16-897 



1/256 



1000-228 



1000131 



1000-097 



0-035 



0-0000152 



0-0038192 



8-960 



24-832 



1/512 



1000-114 



1-000058 



1000-056 



0041 



0-0000178 



00091136 



20-992 



28-672 



1 



§ 70. Specific Gravity. — The observations were made with the two hydrometers 

 3 and 17, and as a rule three series of observations were made with each hydrometer, 

 so that each entry in column S is the mean of six series. The greatest departure of 

 any one value from this mean was 2*2 in the fifth decimal place. 



From m = 1/2 to m = 1/8 the rate of decrease of the increment of the specific gravity 

 (S- 1) is less than that of the concentration. Between m= 1/16 and m= 1/128 there 

 is an approach to a proportion between the rate of decrease of specific gravity and 

 that of concentration, while at ni= 1/256 and 1/512 this decrease is out of all propor- 

 tion to that of concentration, 



§ 71, Displacement, A. — This value refiectsthe nature of changes in specific gravity. 

 If we compare the values of v with those of d^, we see that, between m= 1/2 and 

 m = 1/8, c/A is greater than v ; between m = 1/16 and m = 1/128 their values are nearly 

 identical, and for m= 1/256 and m= 1/512 there is considerable disparity. 



If we take the specific gravity of NaCl in crystal to be 2-15, the sum of the separate 

 displacements of 1 gram-molecule of salt and 1000 grams of water is 1027 '209. The 

 displacement after dissolution has been efi'ected is 1018099, showing a contraction of 

 8 '5 10, When 1/1(5 NaCl is dissolved in 1000 grams of water the increment of displace- 

 ment per gram-molecule, v/m, is 16-272, showing a contraction of 10-937. Here the 

 compression accompanying the act of dissolution reaches a maximum. When the 

 concentration of the solution is less or greater than 1/16 Na(Jl+ 1000 grams of water the 



