(d) This line of proof, strong in itself, is strengthened by observing how land-parcels gradually and practically pass out from the second into the third class of lands,--from the Valuable into the Unvalued. As it is only human Efforts wisely bestowed upon valueless lands or in some connection with them, that ever make these valuable, so it is, that these Efforts intermitted for a time, or less wisely bestowed, or reckoned less in harmony with the present and prospective desires of other men, invariably cause a loss of value in valuable lands; and, if such neglect or unwisdom of effort continue long enough, nothing is more certain, than that lands so treated will lose their value altogether, nobody will give anything for them, they will drop out from the second class into the third by the same path (only in inverse order), by which they crept at first from valueless to valuable. Under the writer's own observation in different parts of New England, whole tiers of farms once valuable and productive have lost that character either wholly or for the most part, taxes can no longer be collected from them, nobody will really give anything for them in exchange, they are abandoned of their former owners, they are left to lie waste or to grow up into forest again. It follows from all this beyond a doubt, and the logical issue is one of vast consequence to mankind, that Value is no attribute of matter, no inherent quality of lands as such wherever situated, but it comes and goes, it is a relation of mutual purchase between human services rendered and received.