“Why,” said the boy, “we are prohibited from illuminating our windows with candles, and I’m going to shoot my candles through the air.”

“Tut, tut, tut,” said Mr. Cossart, laughingly; “that’s an impossibility.”

“No, sir,” said Robert, “there is nothing impossible."[A]

[Footnote A:  He proved that this was not impossible, for he had his display, making his rockets himself, and after his own model.]

“Robert was known,” says one of his biographers, “to purchase small quantities of quicksilver from Dr. Adam Simon Kuhn, druggist, residing opposite the market-house.  He was trying some experiments that he did not wish to make public, and which the workmen in Mr. Fenno’s and Mr. Christian Isch’s shops were anxious to find out, but could not.  He was in the habit almost daily of visiting those shops, and was a favorite among the workmen, who took advantage of his talent for drawing by getting him to make ornamental designs for guns, and sketches of the size and shape of guns, and then giving the calculations of the force, size of the bore and balls, and the distances they would fire; and he would accompany them to the open commons near by potter’s field, to prove his calculations by shooting at a mark.  On account of his expertness in his calculations, and of their ineffectual efforts to discover the use he was making of quicksilver, the shop-hands nicknamed him ‘quicksilver Bob.’

“Mr. Messersmith and Mr. Christian Isch were employed by the Government to make and repair the arms for the troops; and on several occasions guards were stationed at their shops to watch and see that the workmen were constantly employed during whole nights and on Sunday, to prevent any delay.  The workmen had so much reliance and confidence in ‘quicksilver Bob’s’ judgment and mechanical skill, that every suggestion he would make as to the alteration of a gun, or any additional ornament that he would design, was invariably adopted by common consent.

“In the summer of 1779, Robert Fulton evinced an extraordinary fondness for inventions.  He was a frequent visitor at Mr. Messersmith’s and Mr. Fenno’s gunsmith shops, almost daily, and endeavored to manufacture a small air-gun.”

Among the acquaintances of Robert Fulton at this time was a young man, about eighteen years of age, named Christopher Gumpf, who used frequently to accompany his father in his fishing excursions on the Conestoga.  Mr. Gumpf, Sen., being an experienced angler, readily consented to allow Robert to join himself and his son in these expeditions, and made the two boys earn their pleasure by pushing the boat about the stream, as he desired to move from point to point.  As the means of propulsion was simply a pole, the labor was very severe, and Robert soon became tired of it.  Not wishing, however, to give up his pleasant fishing trips, he determined to devise some means of lightening the labor.