2.  I have understood that the price of camphor, at the same time, suffered similar changes.

Chapter 16

On the Influence of Durability on Price

197.  Having now considered the circumstances that modify what may be called the momentary amount of price, we must next examine a principle which seems to have an effect on its permanent average.  The durability of any commodity influences its cost in a permanent manner.  We have already stated that what may be called the momentary price of any commodity depends upon the proportion existing between the supply and demand, and also upon the cost of verification.  The average price, during a long period, will depend upon the labour required for producing and bringing it to market, as well as upon the average supply and demand; but it will also be influenced by the durability of the article manufactured.

Many things in common use are substantially consumed in using:  a phosphorus match, articles of food, and a cigar, are examples of this description.  Some things after use become inapplicable to their former purposes, as paper which has been printed upon:  but it is yet available for the cheesemonger or the trunk-maker.  Some articles, as pens, are quickly worn out by use; and some are still valuable after a long continued wear.  There are others, few perhaps in number, which never wear out; the harder precious stones, when well cut and polished, are of this later class:  the fashion of the gold or silver mounting in which they are set may vary with the taste of the age, and such ornaments are constantly exposed for sale as second-hand, but the gems themselves, when removed from their supports, are never so considered.  A brilliant which has successively graced the necks of a hundred beauties, or glittered for a century upon patrician brows, is weighed by the diamond merchant in the same scale with another which has just escaped from the wheel of the lapidary, and will be purchased or sold by him at the same price per carat.  The great mass of commodities is intermediate in its character between these two extremes, and the periods of respective duration are very various.  It is evident that the average price of those things which are consumed in the act of using them, can never be less than that of the labour of bringing them to market.  They may for a short time be sold for less, but under such circumstances their production must soon cease altogether.  On the other hand, if an article never wears out, its price may continue permanently below the cost of the labour expended in producing it; and the only consequence will be, that no further production will take place:  its price will continue to be regulated by the relation of the supply to the demand; and should that at any aftertime rise, for a considerable period, above the cost of production, it will be again produced.