At this time the plunder of merchandise and naval stores in the River Thames had reached gigantic proportions. Previous to the establishment of the Thames river police in 1798 the commerce of the country, all the operations of merchants and shipowners, were grievously injured by these wholesale depredations, which amounted at a moderate computation to quite half a million per annum. There were, first of all, the river pirates, who boarded unprotected ships in the stream. One gang of them actually weighed a ship's anchor, hoisted it into their boat with a complete new cable, and rowed away with their spoil. These villains hung about vessels newly arrived and cut away anything within reach--cordage, spars, bags of cargo. They generally went armed, and were prepared to fight for what they seized. There were the "heavy horsemen and the light horsemen," the "game watermen," the "game lightermen," the "mudlarks and the scuffle-hunters," each of them following a particular line of their own. Some of these, with the connivance of watchmen or without, would cut lighters adrift and lead them to remote places where they could be pillaged and their contents carried away. Cargoes of coal, Russian tallow, hemp, and ashes were often secured in this way. The "light horsemen" did a large business in the spillings, drainings, and sweepings of sugar, coffee, and rum; these gleanings were greatly increased by fraudulent devices, and were carried off with the connivance of the mates, who shared in the profit. The "heavy horsemen" were smuggled on board to steal whatever they could find--coffee, cocoa, pimento, ginger, and so forth, which they carried on shore concealed about their persons in pouches and pockets under their clothes. The [Illustration: GAMBLING IN SOCIETY. (_From a Print by Gillray, published in 1796._)] "game watermen" worked by quickly receiving what was handed to them when cargoes were being discharged, and this they conveyed at once to some secret place; the "game lightermen" were of the same class, who used their lighters to conceal stolen parcels of goods which they could afterwards dispose of. A clever trick is told of one of these thieves, who long did a big business in purloining oil. A merchant who imported great quantities was astonished at the constant deficiency in the amounts landed, far more than could be explained by ordinary leakage. He determined to attend at the wharf when the lighters arrived, and he saw that in one of them all the casks had been stowed with their bungs downwards. He waited until the lighter was unloaded, and then, visiting her, found the hold full of oil. This the lightermen impudently claimed as their perquisite; but the merchant refused to entertain the idea, and, having sent for casks, filled nine of them with the leakage. Still dissatisfied, he ordered the deck to be taken up, and found between the timbers of the lighter enough to fill five casks more. No doubt this robbery had been long practised.