Thanks for the photos, Adrian. I've seen similar examples of the piece seen in the second pic, and know something of the three chambered "revolver" cannon, but the nine barreled cube mortar is entirely new to me.
This is from ‘The National Cyclopaedia of American Biography’: John Webster Cochran, inventor, was born in Enfield, N.H., May 16, 1814. In 1834 he perfected a revolving breech-loading rifled cannon, constructed upon the principle that afterward made the Colt revolver successful, the cylinder being automatically rotated by the cocking of the hammer. Failing to secure in the United States the capital necessary for its manufacture he visited Paris, France. In, 1835, there he made the acquaintance of the Turkish Ambassador, who became interested in his models and caused Sultan Mahmoud to invite the inventor to Constantinople. Mr. Cochran remained in Turkey for several years and was munificently rewarded by the Sultan for his labors.