Harkaway in London and New York

According to Edwin Brett's own ads in the Boys' of England the Jack Harkaway penny dreadfuls appeared in the following order >

Edwin J. Brett’s Harkaway series.

Vol. I Jack Harkaway’s Schooldays
Vol. II & III Jack Harkaway After Schooldays
Vol. IV & V Jack Harkaway at Oxford
Vol. VI & VII Jack Harkaway Among the Brigands

Jack Harkaway and his Son’s Adventures Round the World >

Vol. VIII & IX Adventures in America and Cuba (1874)
Vol. X Adventures in China (1875)
Vols. XI & XII Adventures in Greece
Vol. XIII Adventures in Australia (1876)
Vols. XIV & XV Young Jack Harkaway & His Boy Tinker

In New York Street & Smith published their own list in 1925 cutting the Brett stories into different lengths and adding new titles. Jack Harkaway Around the World is a reprint of Philip Richards' Adventures in America and Cuba (1874) in 395 pages.