Wherever he went the young inventor and painter was popular. In the near neighborhood of his home there were several factories making arms and ammunition for the war, and guards were stationed about the doors to make sure that no trespassers entered. But "Quicksilver Bob" was allowed to come and go as he would. Whatever he saw he studied, and the first thing they knew the men in charge of the factories would find the boy submitting new plans and new suggestions to them for the improvement of guns or powder. Much to their surprise these suggestions were almost always good ones, and he became a very welcome visitor. He was paid for some of this work, but much of it he did without any reward, except the knowledge that he was in a way serving his country. To help support the little family he used his skill as a painter in making signs for village taverns and shops, very much as another boy artist named Benjamin West had done in his youth. It happened that in 1777 some two thousand British prisoners were brought to Lancaster and quartered there. Such a large number of the enemy naturally caused some alarm among the quiet country people. The officers were lodged at the taverns and at private houses, but the soldiers themselves lived in rude barracks just outside the town, and there were so many of them that they made quite a settlement for themselves. Many of the Hessian troopers had their wives with them, and these occupied square huts built of mud and sod. The little encampment had quite a strange appearance, the small mud houses lining primitive streets and looking like some savage settlement. Naturally the place had a great charm for the Lancaster boys, and whenever they were free from school during that time Robert and his friends were almost sure to be found in the neighborhood of the Hessian huts, watching these strange men who had come from overseas. Fulton drew countless pictures of them, some of them caricatures, but many faithful copies of what he saw. When they were finished these pictures were in great demand, and some of them were carried as far as Philadelphia, to show the people there the curious sights of the country near Lancaster.