Harrow and Dass make a $10 bet but when he has to pay up he hands Dass a red note, meaning it was $20.00 (Australian currency has a different colour for each denomination). However, immediately before the subject of the bet introduces himself, Harrow ups the bet to "double or quits" and loses again, meaning the amount he gives is correct.
When Harrow is writing on the card he plans to give to his daughter, there are two distinct handwriting styles, showing the card had been prepared earlier.