These are distinct formulas under similar names, unlike the duplicated Cassis Fizz. The word original is a source label, not verified historical priority.
Supplied 36-page digital PDF. PDF positions, not print pagination.
Original Singapore Sling on PDF29 combines gin, cherry brandy and lime with very small Benedictine and brandy additions. The Original Singapore Sling on PDF36 gives equal gin, Benedictine and cherry brandy portions with soda and a stirred method.
36
29
Two original Singapore Slings are different recipes
Read against the supplied text and page images. Verified means source fidelity, not tested recipe quality or historical truth.
No access / Whiskey Excerpts Database (USWA)
Source-grounded paraphrase. Verified means fidelity to this supplied copy, not proof that its recipes are correct or tested.
Evidence
Original Singapore Sling on PDF29 combines gin, cherry brandy and lime with very small Benedictine and brandy additions. The Original Singapore Sling on PDF36 gives equal gin, Benedictine and cherry brandy portions with soda and a stirred method.
Location and context
No access, PDF 29–36; supplied PDF positions. Two original Singapore Slings are different recipes. Full analysis 
Annotation
These are distinct formulas under similar names, unlike the duplicated Cassis Fizz. The word original is a source label, not verified historical priority.