Structural and Magneto-optic Rotation. 



421 



experimental investigation of which forms the subject of this 

 paper ; unless indeed it should be possible by superposition of 

 the magneto-optic rotation to completely reverse the structural 

 rotation, i. e., so that the resultant rotation should be of oppo- 

 site sense to the original structural rotation, under which cir- 

 cumstances it might be possible that the molecules would 

 rearrange themselves by swinging over into the enantiomorphic 

 forms possessing that rotation, just as by external force the 

 molecules in a crystal of calcite may be made to slide or swing 

 from one position of equilibrium to another, or from one form 

 to its twin, under the influence of pressure ; the phenomenon 

 being unaccompanied by any serious disturbance such as the 

 disintegration of the crystal. 



However, since the magneto-optic rotation is small, even in 

 the most powerful electro-magnetic fields, the facts observed 

 would appear to be accounted for, and the reversal of the struc- 

 ture would not be expected though an influence might be 

 looked for during the period of formation of the body. 



To determine the truth or error of this supposition, as to 

 the possible control of the final product, by securing conditions 

 favorable to one and antagonistic to the other of the enantio- 

 morphic forms, a large number of crops of sodium chlorate 

 crystals were allowed to grow by spontaneous evaporation in 

 magnetic fields with the results recorded in the following 

 tables.* 



Table II. 

 Crystals grown over N-pole of a vertical bar magnet. 



H 



M 





Or 



No. 



ystals. 



— i , 



Wt. 



Excess by 



Dextro 

 % by wt. 



Remarks. 





No. 



Wt. 





Dextro.. 

 Laevo .. 

 Dextro.. 

 Laevo .. 



5 



9 



1-232 

 0'557 



4 



one crystal 

 not weighed 

 0-675 j 



about 

 60 



68-8 



All large crystals. 

 1 Dextro crystals 

 \ larger than the laevo. 



Dextro . . 

 Laevo .. 



7 7 



42 



0-857 

 0-540 



35 



0-317 



60-9 





Dextro . . 

 Laevo .. 



31 

 31 



0-418 

 0-335 



-- 



0-083 



55-5 





Table II shows the results of four crops obtained over the 

 north pole of a bar magnet. Here the excess of dextro crys- 

 tals in each case is conspicuous, and taken by themselves these 

 results are misleading. Yiewed in the light of the succeeding 

 tables it appears probable that the uniformity here noted is 

 purely accidental. 



* A thin ring of vaseline along the sides of the vessel was found very effec- 

 tual in preventing the creeping of the solution during crystallization. 



Am. Jour. Sci. 

 29 



-Fourth Series, Vol. VI, No. 35. — November, 1898. 



