RO' 



in ItU'ge excess (^i'^^ series N'\ 3) and tlial in siicli a case that [)resent 

 in tlie smallest anionnt is the most strongly impeded. Much more 

 pronounced is the iiindi-ancc observed with mixtures of l^enzoplienone 

 and p. CI- or p. Br-t)cn/>ophenone ; the sum of the pinacones remains 

 here far below the calcidated quantity. The halogen ketone has as 

 a rule a stronger impeding action than benzophenone. for even in 

 smallei' quantities than the molecular ones fN". 2 of the three series) 

 the halogen pinacone in the mixture is predominant. Only with a 

 considerable excess of benzophenone the halogen pinacone is repelled 

 and mostly so in the cases where the greatest hindrance is present 

 (compare N". 3 of the three series). 



We thus find in rough traits what we could expect; there occur, 

 however, particularly when one of the ketones is not reduced 

 separately, such great hindrances that they cannot be satisfactorily 



TABLE XIII. 



