ABSTRACT
The merchant, the producer or a taxing authority has to make a survey of the form of the curve of demand—i.e., ascertain if there is a great or a small difference between the subjective prices of successive units. Otherwise the merchant will not be able to solve the problem, the correct solution of which is the basis of his economic existence; neither would it be possible for the science of finance to find out the effect of taxation on production or consumption. The problem, which is a double one, reads: (a) Will an alteration in the selling price of a thing produce a large or small alteration in the number of effective buyers? and (b) Will an altered output affect the market price perceptibly or not?
