128 Scientific Intelligence. 
. Thesame direction of vibra- 
tion belongs to the color A when 
the observation is in the direction 
of the axis or perpendicular to it. 
To the color A belong, when the 
rite et 20) action on the part of 
the firs 
20. For the same direction of = For nat same direction of vibra- 
vibration and the same wave length tion there are different colors and — 
there is the same color throughout therefore different wave lengths. 
the whole cryst 
The author gertcladen from this reasoning that the assumption ér vie 
brations perpendicular to the plane of polarization leads to clear, simple 
consequent and connected views of the whole subject, while the opposit e 
supposition involves obscure, overloaded and contradictory r nta-- 
tions. Similar spl niin may be drawn from a consideratior ‘of biaxial 
or trichromatig crystals. We must however refer to the original paper 
for a fuller exposition of the authors views and arguments— Pogg. 
Ann., xcvi, 287, Octo 1855. 
2. On the shercton ue the Mellonids.—Lirxzic has at length re- 
newed the discussion of this interesting subjec ct and has established ef 
numerous analyses indirectly the composition of mellonhydric acid a 
of several crystalline and well defined melionids. Mellonhyd 
has the formula CisNisH2. The acid is tribasic and admit 
easily be removed by gentle heating ae 
maine a strongly Bey liquid which expels carbonic acid from 
with effervescence and when neutralized with potash gives orga i 
llonid of potassium. The acid is decomposed by evaporation — i 
sen a white and somewhat crystalline mass which is only partia 
soluble in cold wate ‘ 
Mellonid of potassium crystallizes in very fine silky white need! 
i uo be distinguished fro 
ae 
1 than i 
heat without giving off a trace 
r temperature into cyanogen; 
; double decomposition as & 
In conclusion the 
contains 
