414 M. J. A. Groshans on the Specific Gravity of certain 



Whereas, starting from the values of v and X, which have been 

 obtained by calculation (by means of two experiments for 

 each substance), we have : — 



For KF, 8=2-19; for KC1, 8 = 1*85. 



These figures do not agree so well as those for the sugar • but 

 the agreement appears to us sufficient. 



We see, in using this form of the interpolation-formula 



d=l + 



A + \' 



that when two different substances have the same v (which 

 often occurs), but slightly different values of X, the densities 

 of the two solutions can differ slightly for small values of A; 

 but that the difference diminishes for greater values of A, 

 and that the two densities become equal when A = qo . This 

 result for KF and KC1 may be seen in Table D. 



There are some substances which not only have the same 

 v but also the same X, which occurs (v, v' being assumed 

 equal) when two similar substances have the same specific 

 gravity in the anhydrous state. We will give a single 

 example of this. 



On referring to Landolt's tables, we find for the two follow- 

 ing substances : — 



Mean. 



PbN 2 6 8 = 4-34 to 4-58 4-46 



Srl 2 8 to 10° 4-41 



We have calculated v and X for these substances according 

 to the following experiments of Kremers : — ■ 



Kremers's experiments. 



Srl 2 . 



p. Water, d 19°-5/19°-5. 



27-5 100 1-2160 



127-9 100 1-8349 



PbN 2 6 . 

 p. Water, d 19° '5/19° 5. 



11-10 100 1-0931 



59-02 100 1-4496 



v= 15-7803 v = 15-793 



X= 4-0673 X= 3-970 



Sum ... 19*8476 Sum ... 19-763 



a + /3 =1-046, a + £ =1-0747. 



8calc. = 4-88, 8calc. = 4-98. 



Similar solutions of the two substances with an equal number, 



