2. DAlembert The experiment results show: the rule that for oblique resistance varies with the sine square of the angle of the incidence holds good only for angle between 50 and 90 deg and must be abandoned for lesser angles2. D’Alembert The experiment results show: the rule that for oblique resistance varies with the sine square of the angle of the incidence holds good only for angle between 50 and 90 deg and must be abandoned for lesser angles