William Hill was a Hairdresser/Barber in New York from 1839 until at least 1891. His business locations included: 91 Broad (1839), 118 Water (1840-42), 13 Nassau (1845-55), 1 Barclay (1856-64), 267 Broadway (1868), 60 Warren (1870), 41 Fulton (1872), 9 John (1875), and 427 Fulton (1887-91). I don't know what was at the 1 Barclay address, but Auguste Grandjean had been there around 1840.
Hill advertised his Instantaneous Hair Dye in 1858 and 1863 (below). The Dyes were still listed for sale in the National Druggist catalogs until at least 1898. In 1858, Hill was also selling an "Infallible Ointment for the Growth & Beauty of The Hair." There was a later product in a label only container called "Peruvian Hair Restorative." According to David Schiller, the bottle was aqua, and C. N. Crittenton was the Proprietor. Apparently, Crittenton bought out Hill sometime around 1880. Crittenton registered the brand name (Dye) as a Trade Mark in 1906, and included the label above. He claimed to have been marketing the product since 1880.