392 Intelligence and Miscellaneous Articles. 



sometimes transparent, but is usually cracked in every direction, 

 and only translucent at the margins of its thin fragments. It 

 scratches apatite, and is scratched by felspar. Its density is 2'906. 

 With the blowpipe, it fuses into a transparent glass of a dull green 

 colour ; it is readily attacked by acids and reduced to a thick jelly. 

 Eukolite forms small glassy fragments of a brownish-red colour, 

 sometimes presenting two pretty distinct cleavages, which, as in 

 eudialite, lead to a regular hexagonal prism. Some specimens 

 exhibit a certain amount of transparency, but it is usually fissured 

 in different directions. Its hardness is the same as that of eudialite; 

 its density = 3-007. When examined with polarized light, it exhibits 

 a single optical axis, like eudialite ; with this slight difference, that 

 the axis is positive in eudialite and negative in eukolite. The che- 

 mical characters of both are identical. The following are the average 

 results of several analyses : — 



Eudialite from Greenland. 



Oxygen. Proportions. 



Silica 0-5038 0-2616 \ ^.^-,„^ » 



Tantalic acid 00035 0-0014 / " ^^^" 



Zirconia 0-1560 0-0410 1 



Protoxide of iron 00637 OOHn 



Lime 00923 0-0262 I n-n77'i 2 



Protoxide of manganese 00161 0-0036 r"'' 



Soda 0-1310 0-0336 J 



Chlorine 0-0148 



Volatile matters 00125 



0-9937 



Eukolite from Norway. 



Oxygen. Proportions, 



Silica 0-4570 02372 \ r^.^oaa r 



Tantalic acid 0-0235 0-0027 / " ^^ 



Zirconia 0'1422 0-03641^.^.4,4 1 



Oxide of cerium 0-0249 00050 / 



Protoxideof iron 00683 001521 



Oxide of lanthanium . . 0-0111 0001 6 j 



Lime 00966 00274 VO-0792 2 



Protoxide of manganese 0-0235 0-0053 f 



Soda 0-1159 0-0297J 



Chlorine 0-0111 



Volatile matters 0-0183 



0-9924 



The only difference is the presence of a few parts per cent, of 

 oxides of cerium and lanthanium in eukolite which do not occur in 

 eudialite. By adding the oxygen of the tantalic acid and silica, and 

 that of the oxide of cerium to that of the zirconia, we get the same 

 proportions for eukolite that Rammelsberg assigned to eudialite. 

 These bodies may thus be represented under the same general for- 

 mula,— 6RO + R"-03-f-6Si03. 

 — Comptes Rendus, December 29, 1856, p. 1197. 



I 



