150 
Account ofM. Fresners Discoveries 
opinion which I have expressed on the importance of the cod- 
bank, should coincide with the sentiments of a gentleman much 
better cjiialilied than myself to form a true estimate of the va- 
lue of the discovery. 
Art. XXVII. — Account of M. FresneVs Discoveries respecting 
the Iiiflcxloii of Light. 
i HE inflexion or diffraction of light is a name given to the 
coloured fringes or bands of light which are seen without the 
shadows of opaque substances, and to the dark and luminous 
stripes which are formed within the shadows of minute bodies, 
placed in a divergent beam of light attenuated by transmission 
through a small aperture. 
The successive labours of Grimaldi and Newton threw much 
light on this difficult branch of physical optics ; but it made no 
farther progress till the beginning of the present century, when 
our distinguished countryman Dr Thomas Young gave a fresh 
impulse to the inquiry, and enriched the science with his beau- 
tiful law of interference. 
The application of this law to various inexplicable phenome- 
na of colours, did not fail to attract the notice of different phi- 
losophers ; and such were the expectations of its leading to 
some satisfactory explanation of the phenomena of inflexion, 
^hat it was particularly recommended by the French Institute 
to the notice of the candidates for the prize which tliis distin- 
guished body offered in 1818 for the best Theory of Diffraction. 
This prize was some time ago adjudged to M. A. Fresnel, en- 
gineer of roads and bridges, a philosopher of the highest pro- 
- mise, who had already signalised himself by his researches on 
-the polarisation of light. 
His discoveries respecting inflexion are in the highest degree 
important, and cannot fail to be regarded as affording a strong 
confirmation of the Huy genian theory of light. We have no 
doubt, therefore, that our readers will be gratified with the fol- 
lowing summary of the principal results that are capable of be- 
stated in a popular .manner. 
