6U 



The Rev. S. Haughton on some new Laws 



placed at a fixed azimuth, and the angle of incidence increased, 

 as shown in the first column ; the actual readings of the com- 

 pensator and analyser are given in the second and third columns ; 

 the values of e'— e — 180°, deduced from the compensator by means 

 of equation (9), or a similar equation for the white lamplight, 



are given in the fourth column ; <^ and r, calculated from (7) and 



(8), are given in the fifth and sixth columns; and a seventh 

 column is added containing the values of the angle whose tangent 



is jf found as follows : — If A be the azimuth of the polarizer, 



cos A and sin A will be the components of the incident plane- 



Eolarized light in and perpendicular to the plane of incidence ; 

 ence if a be the reading of the analyser, we have, since I cos a 

 and J sin a are the corresponding components of the reflected 

 light, 



Y=tanacotA (10) 



This column will be found useful in comparing the observa- 

 tions with theory. 



Table III. 

 Azimuth of polarizer =45°. White lamplight (colza oil). 



The fifth and sixth columns of this table prove the truth of 

 Laws I. and V. 



The value of the principal incidence deduced from the values 

 of <!> is 55° 8', at which angle the quantity of light reflected 

 in the plane of incidence (or the major axis of the ellipse) is 

 nearly 104 times the quantity of light in the perpendicular plane 

 (or minor axis) ; because the quantity of light in the plane of 

 incidence is proportional to the square of the ratio of a to b. 



