This may seem like taking Mr. Clark to task for an inconsequential gap in his general information on Digger Indians, Eskimos, and palaeolithic society at large. But the point raised is not of negligible consequence for economic theory, particularly not for any theory of "economic dynamics" that turns in great part about questions of capital and its uses at different stages of economic development. In the primitive culture the quantity and the value of mechanical appliances is relatively slight; and whether the group is actually possessed of more or less of such appliances at a given time is not a question of first-rate importance. The loss of these objects--tangible assets--would entail a transient inconvenience. But the accumulated, habitual knowledge of the ways and means involved in the production and use of these appliances is the outcome of long experience and experimentation; and, given this body of commonplace technological information, the acquisition and employment of the suitable apparatus is easily arranged. The great body of commonplace knowledge made use of in industry is the product and heritage of the group. In its essentials it is known by common notoriety, and the "capital goods" needed for putting this commonplace technological knowledge to use are a slight matter,--practically within the reach of every one. Under these circumstances the ownership of "capital-goods" has no great significance, and, as a practical fact, interest and wages are unknown, and the "earning power of capital" is not seen to be "governed by a specific power of productivity which resides in capital-goods." But the situation changes, presently, by what is called an advance "in the industrial arts." The "capital" required to put the commonplace knowledge to effect grows larger, and so its acquisition becomes an increasingly difficult matter. Through "difficulty of attainment" in adequate quantities, the apparatus and its ownership become a matter of consequence; increasingly so, until presently the equipment required for an effective pursuit of industry comes to be greater than the common man can hope to acquire in a lifetime. The commonplace knowledge of ways and means, the accumulated experience of mankind, is still transmitted in and by the body of the community at large; but, for practical purposes, the advanced "state of the industrial arts" has enabled the owners of goods to corner the wisdom of the ancients and the accumulated experience of the race. Hence "capital," as it stands at that phase of the institution's growth contemplated by Mr. Clark.