How widely the volume of trade differs from the volume of production, and how great is the element of speculative transactions in trade, will best appear, I think, from an analysis of the figures which Fisher gives[245] for the volume of trade in the United States. His figure for the volume of trade in the year 1909 is $387,000,000,000.00, three hundred and eighty-seven billions of dollars! This figure is reached by equating the figures he has reached for MV plus M'V' to PT, and assuming P to be one dollar, by making the "unit" of T, arbitrarily, a dollar's worth of each sort of commodity, at the prices of 1909. I have already commented on the legitimacy of this method of summarizing T,[246] and need not say more here, beyond calling attention to the fact that "volume of trade," as commonly used, does in fact mean, not T alone, but PT. Fisher for years other than 1909, however, makes use of a different method of getting at T: he takes certain indicia of _relative_ amounts of trade, compares them with the same indicia for 1909, and estimates the trade for other years as being such a percentage of the trade for 1909 as their indicia are of the indicia of 1909. The indicia chosen are: (1) quantities of certain commodities, cotton, fruit, cattle, etc., _received at_ principal cities of the United States, taken as typical of the variations of the internal _commerce_ of the United States; (2) quantities of 23 articles of import and 25 articles of export, for each year, taken as typical of variations in the foreign trade of the United States; (3) sales of stocks. These three indicia, weighted in a manner to be described in a moment, are then averaged. There is a second element in the index, made up by taking the figures for railroad _tonnage_, and the figures for _receipts on first class mail_, which are averaged. The first average and the second average are then combined into a third average, which is the final index. The relation between this index for every year other than 1909 and the same index for the year 1909 determines the amount of T for each year--the two indicia, together with the figure, $387,000,000,000.00, giving the required amount by the "rule of three." I shall not go into details with the method of constructing these averages, but I wish to make clear the comparative _weight_ given to each element in the final index: The first three elements count _twice_ as heavily as the last two, and so constitute the biggest factor. In the first average, based on the first three elements, the item taken as typical of internal trade is _weighted by 20_, the item taken as typical of foreign trade is _weighted by 3_, and sale of stocks _by 1_. It appears from Fisher's figures (p. 479), that the one really big _variable_ among all the indicia is the sale of stocks, but the weight given it is so small that it makes virtually no difference in the final result. Thus, as between 1898 and 1899, stock