34 



On Salt- Solutions and Attached Water. 



§ 241a. The quantitative relationship in respect to solu- 

 bility existing between water and triethylamine was deter- 

 mined with considerable accuracy in the following manner. 

 A 50 c. c. burette graduated to two-tenths was sealed at one 

 end, and the mercury and water-meniscus values determined. 

 It was drawn out to a narrow neck, and received about 2 c.c. 

 of mercury. The whole being now counterpoised, a few c.c. 

 of ethylamine were introduced, which proved to weigh 6*86 

 grams. A few grams of water were next added, the end 

 sealed off and dried, and the whole reweighed.. It was found 

 that 7*885 grams of water were present. 



The whole was now brought to a temperature low enough 

 to ensure perfect mixture, and then gradually heated in a 

 large beaker of water to which successive portions of warmer 

 water were added. The water was diligently stirred. When 

 the temperature is high enough to cause separation, the tube 

 is kept at that constant temperature for half an hour, being 

 repeatedly shaken. Taking the level of the mercury as con- 

 stant, and calling it, when corrected for meniscus, 0, we have 

 first the height of the plane of separation of the two liquids to 

 read off. This requires no correction for meniscus at tempe- 

 ratures below 25° C. At 30° and 50° there is some + cur 

 vature (like water); this I have neglected. The height of the 

 upper surface has to be read and corrected for meniscus. 

 (For this the same correction is taken as for water.) The 

 volume of water at 15° was 7*88 c. c, and the volume of tri- 

 ethylamine was 9*5 c. c. On bringing the two together, 

 sufficient heat was set free by the mixture of part to prevent 

 the mixture of the whole. On cooling to 15° the two mixed 

 perfectly, and the volume was 16*6, showing therefore a 

 contraction of 0'8 c. c. At 18°*3 the liquid still remained clear, 

 but at 18°*7, that is in half a degree, a great separation had oc- 

 curred . In the following table the corrected readings are given. 



Separation between water and triethylamine (Triethylamine 

 46*45 per cent., Water 53*55 per cent.). 



At 



15*0 . 



18*3 . 



18*7 . 



19-0 . 



20-0 . 



21*0 . 



22*0 . 



25*0 . 



30*0 . 



50*0 . 



Vol. of lower 



Vol. of upper 



stratum. 



stratum. 







16*6 







16*6 



. 3*5 



13*2 



. 4*5 



12*2 



. 6*1 



11*4 



. 6*8 



10*1 



. 7*2 



9*7 



. 7-8 



9*3 



. 7*9 



9-4 



. 8*0 



9-7 



