Scope of the paper, 217.— I. Elasticities of demand usually obtained by methods which are open to two objections: the time element, 218; data are for markets, 218.— A possible way out, 219.— Data available and method to be used, 220.— II. Coefficients for various commodities, 221.— Substitution, 221.— Relation to income, 224.— III. Spread of consumption around the averages, 225.— IV. Inferences concerning the desirability of price reductions, 229.