_Double competition_ is, when, in a certain degree, it takes place on both sides of the contract at once, or vibrates alternately from one to the other. This is what restrains prices to the adequate value of the merchandize. I frankly confess I feel a great want of language to express my ideas, and it is for this reason I employ so many examples, the better to communicate certain combinations of them, which otherwise would be inextricable. The great difficulty is to distinguish clearly between the principles of _demand_, and those of _competition_: here then follows the principal differences between the two, relatively to the effects they produce severally in the mercantile contract of buying and selling, which I here express shortly by the word _contract_. _Simple demand_ is what brings the quantity of a commodity to market. Many demand, who do not buy; many offer, who do not sell. This demand is called _great_ or _small_; it is said to _increase_, to _augment_, to _swell_; and is expressed by these and other synonimous terms, which mark an augmentation or diminution of quantity. In this species, two people never demand the same thing, but a part of the same thing, or things quite alike. _Compound demand_ is the principle which raises prices, and never can make them sink; because in this case more than one demands the very same thing. It is solely applicable to the buyers, in relation to the price they offer. This demand is called _high_ or _low_, and is said to _rise_, to _fall_, to _mount_, to _sink_, and is expressed by these and other synonimous terms. _Simple competition_, when between buyers, is the same as _compound_ or _high demand_, but differs from it in so far, as this may equally take place among sellers, which _compound demand_ cannot, and then it works a contrary effect: it makes prices _sink_, and is synonimous with _low demand_: it is this competition which overturns the balance of work and demand; of which afterwards. _Double competition_ is what is understood to take place in almost every operation of trade; it is this which prevents the excessive rise of prices; it is this which prevents their excessive fall. While _double competition_ prevails, the balance is perfect, trade and industry flourish. The capital distinction, therefore, between the terms _demand_ and _competition_ is, that _demand_ is constantly relative to the buyers, and when money is not the price, as in barter, then it is relative to that side upon which the greatest _competition_ is found. We therefore say, with regard to _prices_, demand is _high_ or _low_. With regard _to the quantity of merchandize_, demand is _great_ or _small_. With regard _to competition_, it is always called _great_ or _small_, _strong_ or _weak_.