"Well," said Mr. George, after some hesitation, "I am by no means sure that it would not be a good plan for you to buy the watch chain. A gold chain is an article of permanent and intrinsic value. It will last a very long time. Perhaps you would get as much enjoyment from it as from any thing you could buy with that money. At any rate, the money is your own; you have saved it from your travelling expenses by your prudence and economy; and it is right for you to expend it as you take a fancy. If you take a fancy to the chain, I do not know why it would not be a good purchase." "I think I should like the chain very much," said Rollo. "Let us see," said Mr. George, in a musing sort of tone; "there is another way to look at these questions. What is the interest of eight dollars and a half?" "I don't know," said Rollo. "How much is it?" "Let me see," said Mr. George; "seven times six are forty-two--say fifty; and then we must add something for wear, and tear, and depreciation. I should think," he added, after a moment's reflection, "that the chain would cost you about sixty cents a year, as long as you keep it." "How so?" said Rollo. "Why, the money that you will pay for it will produce about fifty cents a year, if you keep it at interest; and of course, if you buy a chain with the money, you stop all that income." "Yes," said Rollo, "I understand that for the fifty cents: and now for the other ten. You said sixty cents." "Why, the chain will be gradually wearing out all the time, while you use it," said Mr. George, "and I estimated that it would lose about ten cents a year. That makes up the sixty." "Yes," said Rollo, "I suppose it would." "You see," continued Mr. George, "that the little links and rings, where the chief wear comes, will gradually become thinner and thinner, and at last the time would come when you could not use it for a chain any longer. You would then have to sell it for old gold; and for that purpose it would not be worth, probably, more than half what you now give for it. "So you see," continued Mr. George, "you would lose the interest on the money you pay for the chain every year; and besides that, you would lose a portion of the chain itself. When you have money safely invested at interest, you have the interest every year, and at the end of the term you have your capital restored to you entire. But in such a purchase as this, you are sure, in the end, to sink a portion of it by wear, and tear, and depreciation; and this circumstance ought always to be taken into account." "Yes," said Rollo; "that is very true." "Making such a calculation as this," continued Mr. George, "will often help us determine whether it is wise or not to make a purchase. The question is, whether you would get as much pleasure from the possession and use of this chain as sixty cents a year would come to." "Yes," said Rollo; "I think I should." "That would be five cents a month," said Mr. George.