THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 



JANUARY 1832. 



I. Oji Experiments relative to the Interferences of Light. By 

 the Rev. Baden Powell, M.A. F.R.S., of Oriel College, Sa- 

 vilian Professor of Geometry in the U?iiversity of Oxford *. 



(].) '' I "'HE beautiful experiments on what has been called 

 -■- diffraction, and those exhibiting directly the phaeno- 

 mena of interference, have acquired the highest interest at the 

 present day, from their connection with the unduiatory theory 

 of light. As however these experiments, partly perhaps from 

 an erroneous impression that they involve considerations of a 

 very difficult and delicate nature, have not been so generally 

 known and repeated as they eminently deserve to be, it may 

 not be thought unsuitable to the pages of a Philosophical 

 Journal, to offer a few detached observations on different points 

 connected with the subject, which I trust may not be useless 

 in affording some aid to the student who is commencing his 

 acquaintance with this part of physical optics, though de- 

 void of any pretensions to profound original research or dis- 

 covery. 



(2.) Newton, observing with great accuracy the external 

 fringes, somehow failed to notice the internal stripes, although 

 Grimaidi had observed the crested fringes at the angles of 

 shadows. 



Maraldi observed that the shadows of cylinders placed in 

 a beam of liglit terminated at a shorter distance than they 

 should do by calculation. He also observed the internal 

 stripes of a shadow. (Biot, Traite de Phys. iv.) 



• Commiinicated by the Author. 

 N. S. Vol. 1 1 . No. 6 1 . Jan. 1 832. B Dutour 



