18 vs. 36 holes on a golf course?

I'm not sure I understand your question, but here goes. In the 1890's, the guys at St. Andrews came up with a way to determine how many holes there would be on a Golf course. The way they did it was this. A bottle of Scotch, drank one shot per hole would last 18 holes. Hence the 19th hole (as the club house bar is referred to) was the "hole" to get a refill. Therefore, it was determined that golf courses be 18 holes.