Antique 1870s G.W. Gray & Son Climatological Map of Maryland & Delaware (32" x 20")"This highly insightful 32" x 20" antique map, titled "Climatological Map of Maryland & Delaware," was published by G. W. Gray & Son, a prominent Philadelphia based firm established in the late 1860s. Renowned for producing one of the most successful atlases and for being "one of the last to employ hand coloring on maps," G. W. Gray & Son's attention to detail is evident here. Likely dating from the 1870s, this unique map visualizes average annual