Striking large scale three-sheet blue-backed sea chart, published by James Imray.
Visually striking and rare sea chart from the California Gold Rush era, pre-dating the first published American charts of the West Coast of North America and almost certainly the best available chart for gold seekers rounding Cape Horn on their way to California. The chart is a working blueback chart depicting the California coast from Cape Corrientes in Mexico northward to Trinidad Bay, California. Two of the land profiles depict approaches to San Francisco, and another is for Monterey. During the first half of the nineteenth century, as the popularity of the sea atlas declined, the rolled blueback chart, issued by private British publishers, became one of the standard navigational aids to merchant seamen. Although published privately, their cartographic and hydrographic information was obtained from official sources, primarily that of the British Admiralty. The firm of James Imray & Son was the foremost publisher of these charts, and the present chart is an outstanding example of the firm's exceptionally fine craftsmanship.
The large blueback chart was intended to be consulted at sea, mounted on tough blue paper, and rolled for ease of storage and spreading out on the charting table. Such blueback charts are especially scarce because of their ephemeral use span, since once obsolete, it was dangerous not to destroy a superseded sea chart. Thus, most working charts did not survive beyond the publication of the next edition. The makers of blueback charts were among the great cartographers of their day, constantly updating and improving their maps. Furthermore, the precarious environment in which sea charts were utilized made them especially vulnerable to damage and loss. They were tools of the sea trade, meant to be used and discarded. This private chart would have been sold to British sea merchants and others plying the Pacific Coast, including the international rush of gold-seekers in 1849.
This chart is as fine as any of the California coast for the Gold Rush era, regardless of format, because it was published and sold in London by James Imray (1803-1870), who owned and operated a "Navigation Warehouse & Naval Academy," the foremost publisher of sea charts. Imray originally was in the stationery and account book publishing business. In 1836 he joined with Michael Blachford, a sea chart publisher based in London. The partnership flourished and soon began to compete with the larger firm of Norie and Wilson. In 1846 Imray bought out Blachford, taking over as sole proprietor. The firm, later led by descendents, survived into the 20th century and is active today.