294 
DR. BREWSTER ON THE PHENOMENA AND LAWS 
restored pencil is likewise — , but always less than 45°, as will appear from the 
following- Table, which contains the greater number of metallic bodies. 
Names of 
Angles of 
Names of 
Angles of 
Metals. 
Restoration. 
Metals. 
Restoration. 
Total reflexions 
o 
. 45 
/ 
0 
Bismuth . . . 
o 
. 21 
/ 
0 
Pure silver 
. 39 
48 
Speculum metal . 
. 21 
0 
Common silver 
. 36 
0 
Zinc .... 
. 19 
10 
Fine gold . . 
. 35 
0 
Steel .... 
• 17 
0 
Jewellers’ gold 
. 33 
0 
Iron pyrites . . 
. 14 
0 
Grain tin . . 
. 33 
0 
Antimony . . . 
. 16 
15 
Brass . . . 
. 32 
0 
Arsenical cobalt . 
. 13 
0 
Tin plate . . 
. 31 
0 
Cobalt ... 
. 12 
30 
Copper . . . 
. 29 
0 
Lead .... 
. 11 
0 
Mercury . . 
. 26 
0 
Galsena . . . 
2 
0 
Platina . . . 
. 22 
0 
Specular iron 
. 0 
0 
The bodies in this Table are obviously in the inverse order according to 
which they polarize most light in the plane of reflexion. 
I have inserted at the top of the Table the inclination of the restored pencil 
in total reflexions, which is 45°; and at the bottom, that of specular iron, 
which is 0° ; in order to show the transition from elliptic polarization to cir- 
cular polarization on the one hand, and to rectilineal polarization on the 
other. 
In these experiments the primitive ray was polarized +45° to the plane of 
reflexion ; but when this angle diminishes, the plane of the restored ray ap- 
proaches to the plane of reflexion, and ultimately coincides with it at 0° ; and 
when this angle increases, the plane of the restored ray recedes from the plane 
of reflexion, and the two planes form an angle of 180° when the other angle 
becomes 90°. 
