Page 156: changed "alumimium" to "aluminium" (Alumina, too, is oxide of aluminium.)
Page 187: changed comma to period at end of sentence (... if the mild steel ordinarily employed for shipbuilding were used.)
Page 188: Deleted spurious comma following "experience" (... as experience shows, a very considerable degree of safety.)
Page 236: changed "nutil" to "until" ( ... which is stored in large accumulator batteries until required ...)
Page 237: added missing period ( ... by long spells of duty in this unhealthy atmosphere.)
Page 307: changed "aliminium" to "aluminium" ( ... another aluminium disc ...)