The formal journal of the IChemE was the “Transactions” which was initially an annual publication.  In order to keep members informed a “Quarterly Bulletin- Institution of Chemical Engineers” was issued.  When the Transactions became quarterly, the Bulletin was issued as a supplement.  In 1956 both changed to bi-monthly and the title was changed to “The Chemical Engineer” with the sub-title “Bulletin of the Institution of Chemical Engineers". It kept the same numbering, so was issue 125. According to the editorial it would contain news and “articles and comments by members, handled less formally than in Transactions, relating both to practical matters arising from experience and to broader aspects of professional life.” 
From 2002 it was published as “TCE” but reverted to its original title with issue 894 in December 2015.