SCIENTIFIC MEMOIRS. 
VOL. I.—PART IV. 
ARTICLE XXV. continued. 
Attempt to explain the Absorption of Light according to the 
Undulatory Theory; by BARON FaBIAN VON WREDE. 
From Poggendortff’s Annalen, vol. xxxiii. Nos. 23, 24 and 25. 
I N order to find its intensity A, I multiply the equation (2) by 
4/ —1 and add it to the equation (1); I then obtain 
A (cosi + “—1.sin i) 
2b —= 2b 
=(l—r)? afi + 7? (cos 2 7 1 V—1.sin2a <) 
+4 (cos2. 2250 4 Y—1.sin2.2n ~") 
2b 
2 —— 
Oka ee "(cos m2 22 + Vi sinn.a, <<) hi 
wh 
or, since 
cosmz + f¥—1.sinmz =(cosz + af ye sin z)” 
A (cost + o/— 1.sini) 
=(—ryaf 1 + r2 (cos 2 =° + V=1.sin2x 5) 
+ r(cos 2° = + V7] .sin2a x) + 
26 Satis 
ee oe (cosa + + Vf, Tsing x 5), 
This is a geometrical series, by the summation of which we obtain 
Vor. L—-Parrt IV. 25 
