26 
Proceedings of the Royal Society of Edinburgh. [Sess. 
the temperature increases ; and since the appearance of the curves is not 
inconsistent with the possibility of intersection in the neighbourhood of 
zero rotation, the observed behaviour is, so far, in agreement with our 
Temperature. 
0° 20° 40° 60° 80’ 100° 120° 140° 160° 180° 
O In cinnamic aldehyde (i? = 9'55). 
® In ethylene bromide (p = 9‘20). 
Fig. 3. — Temperature-rotation curves for m>butyl dibenzoyltartrate in various solvents. 
views. It would obviously, however, be of interest to examine these 
curves towards the right-hand side of the diagram, and, in the hope of 
being able to shift them far enough to link them up definitely with 
those for ethyl tartrate or isobutyl tartrate, 'isobutyl dibenzoyltartrate 
was examined in ethylene bromide and in cinnamic aldehyde solutions, 
