Statistics for occurrence #1 of “Acting-Master, J. H. Johnstone” in chapter 20 of Admiral David D. Porter, The Naval History of the Civil War.:
...ner Dan Smith.--Acting-Master George W. Brown.
Acting-Master, A. M. Gould. Acting-Master's Mate, D. B. Corey.
Acting-Master, Newell Graham. Acting-Master's Mate, Wm. Collins.
Acting-Master, J. H. Johnstone . Acting-Master's Mate, J. A. Chadwick.
Acting-Master, H. B. Jenks. Acting-Master's Mate, G. R. Clifton.
Acting-Master, E. C. Merriman. Acting-Master's Mate, J. W. Comer.
Midshipman, N. W. Th...
† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.