Green’s Dictionary of Slang

Major loder n.

soda water.

1914

Eve. Herald 21 July 2/: Rhyming slang is on the increase [...] but I think the limit was reached the other day by a ‘nut’ who demanded of the lady behind the bar [...] ‘A Watebury Watch and a Major Loder’. The Hebe, who was undoubtedly a ‘nutess’ [...] provided him with a Scotch and Soda.