This Howe truss bridge is one of the longest of the four Howe truss bridges left in Pennsylvania and has stood since 1874. William Howe patented the design in 1840, creating the first bridge system to use iron with wood and a forerunner of all-iron bridges. His design let builders use green wood and adjust iron rods with turnbuckles as the wood seasoned or shrank, so they often returned a year later to tune up the spans. It also made factory production possible, with foundries producing iron rods, nuts, and patent angle blocks while builders used almost any good wood. In Pennsylvania, pioneers urgently needed bridges because even small streams became dangerous in high water, and bridge building evolved rapidly from simple stringers laid across a creek, to added triangles for support, to truss forms that used triangles to carry weight and loads. Wood was the cheapest and most abundant material, and covering a bridge protected its supporting trusses from rot. Most bridges were privately built as toll bridges or to serve mills, since governments were not yet in the bridge-building business. Owners offered discounts to doctors, clergy, and large families, waived tolls for Sunday church-goers, and mill-owned bridges did not charge people hauling grain to the mill. Charge accounts were common, with farmers keeping tallies scratched on wagon seats. Little-used bridges also served as shelters for meetings, church services, and rallies, were used for advertising, gave youngsters rafters for acrobatics, sometimes harbored robbers, and became known as kissing or wishing bridges where sweethearts kissed in the darkness and travelers made wishes.