272 



J. II. Long — Circular Polarization of 



amount of water was held by the product dried over sulphuric 

 acid. With the salt thoroughly dried I obtained higher results, 

 as are shown in the following: table. 



em. in 100 cc. 



D- 



[a] 



4-862 



11-600 



58101 



9-416 



25-388 



63-581 



13-861 



40-036 



66843 



18-038 



54-534 



68-287 



5 gm. KBOC 4 H 4 6 . 1-0266 



10 " " " 1-0533 



15 " " " 1-0803 



20 " " " 1-1068 



The values are seen to be larger than with the other prepar- 

 ations. For the concentration C = 5 - 488 at £=20°, Landolt 

 found [a]=58 0, 35. The variation of the specific rotation with 

 increased strength of solution is shown by the curve E. In 

 order to represent this with the others, the values of [a] were 

 divided by 10, and the quotients so obtained diminished by 3. 

 That is, the axis of abscissas is assumed to be 3° below. 



The effect of addition of inactive salts is shown in the fol- 

 lowing table, 10 gm. of KBOC 4 H 4 O e being used : 



Formula and 

 amount of 

 inactive salt. 



KC1 5 



NaCl 5 



NaBr 5 



Na 2 S0 4 (dry) 5 



gm. 



KN0 3 



NEUC1 

 H3BO3 

 H 3 BO, 



Observed 



Specific 



Deviation 



rotation 



rotation 



from 



a. 



[a.] 



normal. 



25-503 



63-865 



+ 0-284 



25-893 



64841 



+ 1-260 



27-090 



67-840 



+ 4-259 



27-600 



69-117 



+ 5-536 



25996 



65-105 



+ 1-524 



29-160 



73-024 



+ 9-443 



26-726 



66-928 



+ 3-347 



27-260 



68-265 



+ 4-684 



27-788 



69-587 



+ 6-006 



In this table the behavior with the acetate is again charac- 

 teristic, but it must be said that in any case the increased 

 rotation appears singular. Bearing in mind that the specific 

 rotations of potassium tartrate and sodium tartrate are about 

 half as great as that of the potassium boro-tartrate we should 

 naturally expect a reduction by addition of either potassium or 

 sodium compounds to the latter just as has been shown to take 

 place in the case of potassium antimony tartrate or thallium 

 antimony tartrate. 



The specific rotations of the neutral tartrates of potassium, 

 thallium, sodium and ammonium are known, as are also the 

 rotations of the various double tartrates of these metals. I 

 have shown in my former paper that the rotation of potassium 

 sodium tartrate may be modified ; that is, made to approach 

 that of potassium tartrate or sodium tartrate by adding on the 

 one hand a potassium salt, or on the other hand a sodium salt, 

 and this apparently without exception. 



The experiments in this paper on the double tartrates of 

 thallium, potassium, sodium, ammonium and lithium seem to 



