( 303 ) 



In the last line of this table the values of the molecular rotatory 

 power for Na-light divider] by that of water, are given according 

 to the example of Peukin ^). Although it appears from his investi- 

 gations and those of others that the calculation of the molecular 

 rotatory power of a chemical compound as the sum of that of its 

 atoms does not hold good throughout, it may be interesting to 

 compare Pekkin's atomic rotations with those resulting from our 

 observations. From the above-mentioned values of the molecular 

 rotatory power follows for 1 atom : 



= Ü.265 

 X = Ü.281 

 H = 0.285. 



Pekkix Hndö for oxygen 0.104 or 0.261 according to the way 

 of composition, and for hydrogen 0.254, numbers as we see of the 

 same order. Perkin's number 0.717, calculated for nitrogen in amines 



1) Pekkix. J. of Chem. Soc. 45, p. 421 (1S84), and following volumes. 



