464 Mr. E. Wilson. 



Amorphous black cinnabar=Hg:]jSS=ll X 5*52=6072 = 2 x 30*36 obs. 

 vol. o0-36. 



Red rhombohedric cinnabar =Hg;;Sjj= 11 x 5*30 = 58*30=2 x 29*10 obs. 

 vol. 29*10. 



The black cinnabar is distinguished from the red by the fact that, 

 in the former, the mercury stere dominates, whilst in the latter it is 

 the sulphur =5*30. 



The mercury in its chlorides and bromides, and also in the cyanide 

 is present as Hgf, and not as Hg|, thus : — 



Mercurous chloride =Hg|Clf= 6 x 5^52 =33*12 obs. vol. = 33*12. 



bromide=HgBrj=7 x 5*52=38*64 „ „ =38*64 

 Mercuric chloride =HgJClS = 9x^52=49*68 „ „ =49-68. 



bromide=Hg?Brf=llx 5^52=6072 „ „ =60*72. 



cyanide=HgOyl=12 x 5*52=66*24 „ „ =66*24. 



Manganese oxides and silicates. — Metalic manganese has, according 

 to John, the volume 6*9 = |- magnesium. 



Mn^=5x5 7 52=27*6=4x^9 obs. vol. = 6*9. 

 Pyrolusite=MnJ01=13 X 5*52= 71*76 = 4 x 17*94 obs. vol.-17*8-18*0. 



Manganite is isomorphous with gothite and diaspore. 

 The molecular volumes of these bodies are as follows : — 



Diaspore=AllH 1 ,Ot=7x5 : l4=35*98 obs. vol. = 35*98. 



Manganite =MnJHJO|= 15 x 5*40=81 = 2 x 40*5 obs. vol.=40*5. 



G6thite=FeIH10|=15 x 5*40=81 = 2 x 40*5 obs. vol.=40*5. 



In diaspore, therefore, the aluminium stere dominates, but in man- 

 ganese and gothite the oxygen stere = 5*40. 



All the other oxides of manganese contain the manganese as Mnij, 

 thus : — 



Manganous oxide=Mn|0^=5 x 5^52=2 x 13*80 obs. vol.=13*80. 

 Braunite „ =Mn|Q|=6 X 5*52 =33*12 obs. vol. = 33*12. 



Hausmannite „ -=MnjjOf=17 X 5 T 52 = 93*82 = 2 x 46*91 obs. vol. = 

 47*1 0. 



In the manganese silicates, the manganese has the condensation 



