MODERN FRIEDEL-CRAFTS CHEMISTRY . XVII: STUDIES ON THE ACID-CATALYSED DEHYDRATION OF 3-(ALPHA -NAPHTHYLMETHYL)-3-PENTANOL, 2-(ALPHA -NAPHTHYL)-1,1-DIP HENYL-1-ETHANOL AND 2-METHYL-2-(ALPHA -NAPHTHYL)-2-BUTANOL