An early allegorical map on temperance, accompanied by a lengthy poem. Typical of "didactic" visual aids intended to be "at once entertaining and instructive . . . . colorful and intricate temperance maps depicting the 'Ocean of Life' trained viewers to see that the path to damnation was . . . a veritable riptide towing the sinner from the first sip of grog to the channel of destruction. The apparent innocuousness and swift danger of water made it a potent metaphor for life's temptations in an era when waterways were primary transportation routes, and accidental drownings and shipwrecks not uncommon. The maps vividly showed that 'Religion Channel' was just one strong current away from 'Misery Regions' and the 'Reprobate Empire,' not only for seasoned tipplers but for all on the 'Ocean of Life.'" (Lum 2014, 90). For a similar, earlier allegorical map, see ID #1049 (Wiltberger, Temperance Map).
Murrell had written a book on his service as a sailor on a frigate from 1839-1840, and one passage in the book suggests that his disgust at intemperance during these voyages may have led him to reform (Buehler, Michael, http://www.bostonraremaps.com/catalogues/BRM2216.HTM, accessed January 6, 2015).
Ocean voyages have often been used in allegorical mapping. See Subjects > Allegorical.