Consumer 's surpius:-

The theory of consumer 's surplus was propounded by the famouse french engineer Arsene Jules Dupuit in the year 1844a.d. While constructing a bridge over a river the possibility of public surplus came into his mind .for the calculation of the possible surplus he gave the concept of consumer surplus.An engineer rather than an economist his concept remained in complete.

Marshall in his book"pure theory of domestic value "explained this theory very cleary under the topic 'consumer 's rent .In his book 'principles of economic he replaced consumer 's rent by the theory of consumer surplus .The credit for developing the theory of consumer 's surplus scientifically goes to marshall.