Cryptic

I love a good cryptic crossword.  Untangling words is a real source of joy for me.  This particular crossword has an additional level of difficulty in that the clues have no numbers to indicate where they go.  I only know that the clues are in alphabetical order - with some letters having more than one clue.

I've just opened it up for my second stab at it.  One clue I didn't get yesterday jumped out at me today "A chum having half an hour with first of scientific dabblers (8)" - simple if you know how to play.

A Chum = A MATE
half an hour = UR (the third and fourth letters of hour)
first of scientific = S (first letter of scientific)

Put them together and you get AMATEURS or dabblers.

Easy when you know how.