454 Scientific Intelligence. 
nite direction, an increase in the temperature producing tints 
extending more and more toward the red end of the spectrum, 
et finally brown and black if the heat be sufficiently in- 
(2) That in sore ZOE an inerease in the quantity of the 
negative element produces a change of color toward the red end 
of the spectrum, ending finally in brown and black; for example, 
PbO is yellow, Pb,O, red a and PbO, brown. Carnelley formulates 
the third condition thus: In certain scries of compounds A,R,, 
while A, B, C, etc., are elements belonging to the same sub-groups’ 
in Mendelejeft’s table of natural classification of the elements, the 
color varies either entirely or partially through the following scale 
of color as the atomic weight rises: White (or colorless), violet, 
indigo, a green, yellow, orange, red, brown and black; in 
884. 
# Analysis under greatly diminished aon slomeae 
ress and Srusert have made a series of experiments on the 
force of gaseous pap ouies under reine pressure, the sewnlis 
of which confirm the observation of Thomas that rarefaction pro- 
duced by Coie the pressure is more “effective i in pene ning 
é 
