K W. Clarke— Note on Molecular Volumes. 293 



for LiCl, NaCl, KC1, NaBr, KBr, Nal, and Kl, or seven com- 

 pounds in all. To these I added, though unsatisfactorily, the 



corresponding salts of silver, making a list of ten bodies closely 

 related, and giving volumes multiples of 5-5. the value assigned 

 by Kopp to hydrogen in its liquid compounds, at their boiling 

 points. This relation I am now able to extend, partly by new 

 density observations of my own, to include at least twelve 

 compounds not in my earlier list. 



My own determinations, in addition to those I have already 

 given for the alkaline fluorides, are as follows: Rubidium 

 chloride, 2-209, 19°; rubidium bromide, 2'780, 17-5°; rubidium 

 iodide, 3-023, 22°; lithium bromide, 3-102, L7 J ; lithium iodide, 

 3-485, 23°. 



Now let us tabulate the material. The first column contains 

 the symbol of the substance, the second its density with author- 

 ity given, the third its molecular volume as found, the fourth 

 its volume calculated, the fifth a theoretical density deduced 

 from this volume. The calculated volumes are of course the 

 exact multiples of Kopp's hydrogen value, and will be seen at 

 once to agree closely with the results of experiment. The real 

 variation between fact and theory, however, will be best seen 

 upon comparing the two columns of densities. The differences 

 here are always less than 0"1. 



I. 



II. 



in. 



IV. 



v. 



LiF. 



2-295, Clarke. 



11-33 



1100 



2-363 





1-998, Kremera. 



21-27 





1-932 



Li Br. 

 Li I. 



3-102, Clarke. 



28-05 



27-50 









38-50 



3-481 









1650 





NaCl. 



2-145,' Buignet. 



27-27 



27-50 





NaBr. 

 Nal. 



3-079, Kremers. 





33-00 



3-121 



3 450, Filhol. 



43-48 









2-096, Clarke. 



28-20 



27-50 





KBr". 

 KI. 



Kb p. 



1-945, Kopp. 



2-672, Flayfair, Joule. 



44-57 



4400 



2-707 



3 056, FilhoL 



5435 











33 00 





Rba 







55-00 



2-200 



RbBr. 





5953 



60-50 



2-735 



Jlbl. 



3-023^ " 



7029 



71-50 



2-972 



have sixteen compounds 

 ' which agrees with the rule. 



sn:,k 



molecular volu^wmes outTa mult^leof' 5t, „. 



Un 'y one substance in the list seems to be in any way abnormal, 

 rubidium fluoride, with its volume of 83. The other 

 fluorides in this group have volumes less by 11 than those of 

 ™e corresponding chlorides, but f " 

 ££ - A curious progressive relati 



, _j the differs 

 i also worth noting. 



