Chemistry and Physics. 148 
ously employed for this purpose. He wound the wire around a 
clay pipe enclosed in a muffle and immersed the whole in a bath 
of water, mercury, sulphur or cadmium, which was kept at the 
boiling point by a Perret furnace. Constant temperatures of 100°, 
60°, 440° and 860° were thus obtained. Various temperatures 
h. The meas- 
e 
results graphically. They show that the resistance increases regu- 
larly for all metals like tin, lead and zinc up to their point of 
fusion, This increase, however, differs for different metals. 
hotice that tin, thallium, cadmium, zinc, lead, are found together 
m the upper part of the plate; at 200° to 230° their resistance 
has doubled. Below them are iron and steel; for the last the re- 
sistance doubles at 180°, quadruples at 430°, and at 860° is about 
old, copper and silver form an intermediate group. In general 
B.C. P. 
ne Reflection by Glass.—Dr. P. Guan has measured the amount 
of light reflected by a plate of glass and compared the results 
h 
enee table the first column gives the angle of inci- 
the ge, ‘ 
Second the mean of twelve observations of the amount 
