Particularly was this true in the case of the Revolution. Only a small portion of the American people lived in towns. Countrymen back from the coast were in no way dependent upon them for a livelihood. They lived on the produce of the soil, not upon the profits of trade. This very fact gave strength to them in the contest. Whenever the British ventured far from the ports of entry, they encountered reverses. Burgoyne was forced to surrender at Saratoga because he was surrounded and cut off from his base of supplies. As soon as the British got away from Charleston, they were harassed and worried by the guerrilla warriors of Marion, Sumter, and Pickens. Cornwallis could technically defeat Greene at Guilford far in the interior; but he could not hold the inland region he had invaded. Sustained by their own labor, possessing the interior to which their armies could readily retreat, supplied mainly from native resources, the Americans could not be hemmed in, penned up, and destroyed at one fell blow. =The Sea Power.=--The British made good use of their fleet in cutting off American trade, but control of the sea did not seriously affect the United States. As an agricultural country, the ruin of its commerce was not such a vital matter. All the materials for a comfortable though somewhat rude life were right at hand. It made little difference to a nation fighting for existence, if silks, fine linens, and chinaware were cut off. This was an evil to which submission was necessary. Nor did the brilliant exploits of John Paul Jones and Captain John Barry materially change the situation. They demonstrated the skill of American seamen and their courage as fighting men. They raised the rates of British marine insurance, but they did not dethrone the mistress of the seas. Less spectacular, and more distinctive, were the deeds of the hundreds of privateers and minor captains who overhauled British supply ships and kept British merchantmen in constant anxiety. Not until the French fleet was thrown into the scale, were the British compelled to reckon seriously with the enemy on the sea and make plans based upon the possibilities of a maritime disaster.