12 



SPECIFIC ROTATION OF VARIOUS PROTEIDS. [BOOK I. 



placed in the tube T. Both the directions of vibration OS, Off will be turned 

 through equal angles in the same direction, and their components along SP 

 will be no longer equal, and one half of the field will appear brighter 



Fig. 6. 



than the other (Fig. 6, B or C). If the prism be now turned round 

 by means of the screw G till we again have equal illuminations in the 

 two halves of the field (Fig. 6, A), SP has evidently been turned through 

 the same angle and in the same direction as that through which the liquid 

 has rotated the planes of polarization OB, OK, and the reading of the 

 instrument in its new position at once gives us the angle of rotation. 



TABLE EXHIBITING THE SPECIFIC ROTATION OF SOME OF THE CHIEF 

 PROTEID BODIES FOR THE YELLOW LINE D. (COMPILED FROM THE 

 OBSERVATIONS OF HOPPE-SEYLER 1 AND HAAS 2 .) 



1 Hoppe-Seyler, Zeitschrift f. Chem. u. Pharm. 1864, p. 737. 



2 Haas, "Ueber das optische und chemische Verhalten einiger Eiweisssubstanzen, 

 inabesondere der dialysirten Albumine." Pfluger's Archiv, vol. xn. pp. 378--410. 



