second class land of 1 quarter. (Ch. 2.)] [Footnote 150-5: _von Thünen_, der isolirte Staat, II, I, 179, estimates that a bed of manure 1/3 of an inch thick on an acre of ground, increases the production by ½; that a second ½ inch of manure increases the yield only by a + of 5/8 corn; the third of ¼ corn, etc. _Geyer_ is of opinion that, in Saxony, land of the average quality will yield a gross product of 60 thalers per acre, and 14 thalers net product per acre, in case it is managed with the greatest intelligence and the employment of a large amount of capital; when managed in a very ordinary way, it would yield 20 thalers gross, and 7½ thalers net product. _Thünen_ gives the following formula determining when it is more advantageous to cultivate the old land with more _intensiveness_ (higher farming) than to begin the cultivation of new: As long as p - _a_q is less than sqrt(ap), so long is an increase of the outlay of capital on the same land more profitable than the cultivation of new land, and _vice versa_. Here p = aggregate product obtained by a workman in a year from the amount of capital used by him; a = sum of his necessary yearly wants; _a_ = the interest per annum of a capital = p; q = the amount of capital given to assist the individual workman.] [Footnote 150-6: _Ricardo_ had, in every case in which outlay of capital and labor of different degrees of productiveness had to be used on the same land, to suppose a price of the products = the cost of the least productive outlay. See the tables in _Ricardo's_ work, On the Influence of a low Price of Corn on the Profits of Stock, 1815, 14 seq. _Schmoller_, on the other hand, rightly applies the principle of united costs of production in as far as the usual amount of profit of the producer is added to the cost of the commodity with the highest cost of production. Mittheilungen des Landwirthsch. Instituts zu Halle, 1865, 128. Compare _supra_, §§ 106, 110.] SECTION CLI. THEORY OF RENT.--LAND FAVORABLY SITUATED. The favorable situation of a piece of land operates, in almost every politico-economical respect, in the same manner as its fertility.[151-1] If a market, to be fully supplied, needs to be fed from a circuit of ten miles, the price must be sufficient to make good not only the other cost of production but the freight over ten miles. Here, therefore, all producers living nearer to the market, who have to make a smaller outlay for transportation and yet obtain the same market price for their produce, make a profit exactly corresponding to the advantage of their situation.[151-2] The situation of individual pieces of land relatively to farm buildings, etc., operates in a similar way.[151-3]