no Captain Kater on the best kind of steel 
The steel of which these needles were made had been 
exposed to a sufficient degree of heat to render it soft enough 
to be worked, and in this state the needles were magnetized. 
Experiment 4 . 
Steel soft as worked. 
Directive 
force. 
Parallelogram 
720 
Small rhombus 
53° 
Large rhombus 
7 6 5 
Pierced rhombus - 
813 
Experiment 5 . 
The ends of the needles hardened at an 
Directive 
obscure red heat. 
force. 
Parallelogram 
715 
Small rhombus 
577 
Large rhombus 
79° 
Pierced rhombus - 
840 
Experiment 6. 
The ends hardened at a red heat. 
Directive 
force. 
Parallelogram 
74 2 
Small rhombus 
58s 
Large rhombus 
745 
Pierced rhombus - 
844 
