These facts show what a poor circulation the Post-office had at the period in question, and what splendid intervals there were in which to sort the correspondence. Nowadays, in any office pretending to importance, the letters pour in all day long (and all night too, possibly), and they pour out in a constant stream at the same time--letters being in and out of an office in certain instances within the space of a few minutes. A good sorter will sort letters at the rate of 25 to 40 a minute. But let us look at what a sorter has to learn to do this. A leaf of the circulation book in use at Edinburgh for places in England is here inserted (p. 131), which will be of assistance in understanding the matter. It will be observed that there are seven times in the day at which despatches are made to England. Letters for Martock, in Somersetshire, for example, in accordance with the hour at which they may be posted, would be sent thus: to Birmingham at 10.0 A.M.; to the Midland Travelling Post-office Forward, third division, at 2.40 P.M.; no circulation at 4.15 P.M.; to the Glasgow and Carlisle Sorting Tender (a sorting carriage running between these towns) at 5.50 P.M.; no circulation at 7.20 P.M.; to the Bristol and Exeter Travelling Post-office at 9.0 P.M.; and to London at 10.0 P.M. Then if we take Mitcheldean, at the foot of the sheet, its circulation is this: to Birmingham at 10.0 A.M.; to Gloucester at 2.40 P.M.; to the Glasgow and Carlisle Sorting Tender at 5.50 P.M.; to Gloucester at 9.0 P.M.; and to Manchester at 10.0 P.M. And so on throughout the book, which contains the names of some 1300 places in England. Nor, as regards England, is this all. The sorters have to divide letters into the several London districts by reference to the street addresses which the letters bear. Again, these men have to know the circulation for Scotch towns and Irish towns, and many of them have, besides, such a knowledge of the streets of their own city, Edinburgh, as enables them to sort letters for delivery into the several postmen's districts. Thus it will be seen that the sortation of letters is no mere mechanical process, but demands considerable head-work, as well as activity of body.