256 Dr. H. Kopp on the Atomic Volume 



This law may be proved from facts already known. The 

 following presents a tabular view of all the isomorphous 

 groups, the specific gravities of which have been determined 

 with accuracy. In the first column the chemical formulas of 

 the compounds are stated ; in the second their specific gra- 

 vities, with the authorities from which they are taken ; in the 

 third the atomic weights adopted by Berzelius ; and in the 

 fourth the atomic volumes deduced from the observations. 

 Gold a7id Silver. 

 Au ] 9-258 Brisson 1243-0 64-54 



A in (OQ V . r 1351-6 129-61 



Ag 10-428 Karsten. | g^^.g g^.g^ 



Berzelius has given the number 1351 as the atomic weight 

 for silver, but Regnault has lately proved that 675 is more 

 correct. 



Potassium and Sodium. 

 K 0-865 Gay-Lussac and Thenard 489-92 566-39 



Na 0-972 f 290-90 299-27 



^^ "'''"' " " " 1581-80 598-54 



Dr. Clarke, influenced by several theoretical considerations, 

 was induced a few years since to propose that the atomic 

 weight of sodium should be raised twice as high as it is con- 

 sidered by Berzelius to be ; and it is remarkable, that we ob- 

 tain an equal atomic volume between potassium and sodium, 

 if we adopt the view of Dr. Clarke. 



O.vide of Tin and Titanic Acid. 

 So Oo 6-900 Mohs 935-20 134-38 



•202\n .,, , 1 rl 19-87 



.054 J Breithaiipt 1 ' 



118-40 

 TiO., ^4-249 Mohs V 503-69 J 118-54 



3-759 Bi-eithaupt 134-00 



13-826 Mohs J 1.131-65 



The first three numbers for the specific gravity of titanic 

 acid are deduced from the mineral rutile, which is always 

 rendered impure by substances specifically heavier ; its atomic 

 volume must, therefore, be smaller than it really is. The two 

 last are drawn for anatase. 



Alumina, Peroxide of Iron, O.vide of Chromium and Ilmenite. 



r3-909\ !>, , -) ri64-.32 



I 3.979 j Mohs I l^gj.^3 



Al, O. <! \f^) Breithaupt j> 64233 <j j^^;g 



j 3-562 Musschenbroek | | 180-33 



L3-531 Brisson J L181-93 



r5-225 Boullay "j r 187-26 



Fe.03<^^|J)Leonhard >978-43 j^J^^ 



L5-251 Mohs J L 186-33 



