The family then lived in the wilderness, surrounded by a pine forest, where Ericsson's father was engaged in selecting timber for the lock-gates of a canal. A quill and a pencil were the boy's tools in the way of drawing materials. He made compasses of birch wood. A pair of steel tweezers were converted into a drawing-pen. Ericsson had never seen a wind-mill, but following as well as he could the description of those who had, he succeeded in constructing on paper the mechanism connecting the crank of a wind-mill with the pump-lever. The plan, conceived and executed under such circumstances by a mere boy, attracted the attention of Count Platen, president of the Gotha Ship Canal, on which Ericsson's father was employed, and when Ericsson was twelve years old he was made a member of the surveying party carrying out the canal work and put in charge of a section. Six hundred of the royal troops looked for directions in their daily work to this boy, one of his attendants being a man who followed him with a stool, upon which he stood to use the surveying instruments. The amusements of this boy engineer, even at the age of fifteen, are indicated by a portfolio of drawings made in his leisure moments, giving maps of the most important parts of the canal, three hundred miles in length, and showing all the machinery used in its construction. His precocity was, however, the normal and healthy development of a mind as fond of mechanical principles as Raphael was of color. It was in 1811 that Ericsson made his first scale drawing of the famous Sunderland Iron Bridge, and from that time on his career in Sweden was a brilliant one. After serving as an engineer upon the Gotha Canal he became an officer in the Swedish army, from which circumstance he got his title of captain. Most government work was then done by army officers, especially in field surveying. The appointments of government surveyors being offered soon afterward to competitive examination among the officers of the army, Ericsson went to Stockholm and entered the lists. Detailed maps of fifty square miles of Swedish territory, still upon file at Stockholm, show his skill. Though his work as a surveyor exceeded that of any of his companions, he was not satisfied. He sought an outlet for his superfluous activity in preparing the drawings and engraving sixty-four large plates for a work illustrating the Gotha Canal. His faculty for invention was shown here by the construction of a machine-engraver, with which eighteen copper-plates were completed by his own hand within a year.