I wasn't sure where to put this but I decided that it was most closely associated with the threadless era of insulators. It is an original receipt (very brittle and fragile!) for telegraph services to the Pennsylvania Telegraph Company. These lines were put into service in 1846 according to the historical sources: Old Wires and New Waves-by Alvin Harlow as well as Wiring a Continent- by Robert L. Thompson. As you can see the receipt is dated 1847. This places this document within 2 years of the invention of the telegraph by Samuel Morse in 1845! At that time there were only a handful of telegraph lines in operation. This particular telegraph line was erected along the Harrisburg and Lancaster Railroad (Pennsylvania).