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XLV. On the Specific Gravity of certain Substances in the Solid 

 State and in Aqueous Solution. By J. A. Groshans*. 



rSEFUL compilations, like those of Landolt and Born- 

 vJ stein f, render easy the observation of certain physical 

 properties characterizing whole classes of bodies. We have 

 been studying the specific gravities of some solid substances, 

 and we will proceed directly to the discussion of one or two 

 particular cases. 



Analogous Compounds of Potassium and Sodium. 



The atomic weight of sodium is 23 and its specific gravity 

 0*97; the atomic weight of potassium is 39 and its specific 

 gravity 0*87 : sodium is the heavier of the two. 



We find an apparent anomaly in all the compounds of these 

 two bodies : in the solid state the sodium compound possesses 

 a greater specific weight than that of the analogous compound 

 of potassium, the two specific gravities bearing to one another 

 the mean ratio of about 1*10 to 1. But for aqueous solutions, 

 with an equal number of molecules of water (for example 100 

 and 200), the reverse is true ; for then the density of the solu- 

 tion which contains the potassium is always greater than the 

 one containing the sodium. Table A shows the first case. 



Table A. 



The Specific Gravities, at the ordinary temperature, of the 



analogous compounds of Potassium and Sodium- 



Example. 



Potassium 

 compound. 



Specific 

 gravity. 



Sodium 

 compound. 



Specific 

 gravity. 



Ratio of 



specific 



gravities. 



1 



2 



3 ...'.'.'. 



I 4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



KC1 



KBr 



KI 



KF 



KN0 3 



KCIO3 



KBr0 3 



KIO3 



KPO3 



KOH 



K,S 



k;co 3 



K 2 S0 4 



1-977 

 2-690 

 3-070 

 2-481 

 2-092 



2-331 

 3-240 

 3-890 

 2-258 

 2044 



2130 



2-290 

 2-647 



NaOl 



NaBr 



Nal 



NaF 



NaN0 3 



NaC10 3 



NaBr0 3 



NaI0 3 



NaP0 3 



NaOH 



Na.,S 



Na^COg 



Na.,S0 4 



2-150 

 3014 

 3-550 

 2-766 

 2-130 



2-289 

 3-339 

 4-277 

 2-476 

 2130 



2-471 

 2-476 

 2-655 



1-087 

 1-120 

 1-165 

 1-115 

 1-197 



0-982 

 1-030 

 1-100 

 1-211 

 1042 



1079 

 1-081 

 1-003 



Mean ratio 



1095 



* Communicated by the Author, and translated from the French by 

 Frederick H. Hatch. 



t Physikalisch-chemische Tabellen (Berlin, 1883). 



