124 Progress in Science. January, 
(Figs. 1 and 2). Associated with these molecular changes are others relating 
to the heating and cooling of wires of the magnetic metals. Mr. Gore dis- 
covered that an iron wire, when raised to a white heat, underwent an anomalous 
expansion at a certain point during its cooling. On repeating Mr. Gore’s 
Fic. 2. 
experiments, the author found a similar anomalous deportment during the 
heating of iron wire,—the wire momentarily contrating when the temperature 
of a Vull red heat was reached, and, as far as the eye could judge, this was 
also the temperature at which the elongation occurred in cooling (Figs. 3 and 4). 
FIG 3. 
20 30 
10 40 
red hot 
brighe red 
alt 
Fic. 4. 
Examining the wire during the experiment, in a darkened room, another 
remarkable phenomenon was revealed, viz., that at the critical point during 
the cooling of the wire a sudden glow diffused itself over the wire, whereby it 
was raised from a dull to a bright red heat. During the heating of the wire— 
whether by an electric current or by a row of gas flames—a momentary cessa- 
tion of heating occurred at the critical point. Enclosing the wire in an air 
thermometer, these effeéts were made more evident,—the expansion of the air 
during the heating of the wire ceasing for a moment, when a dull red heat was 
