how accurately measure the reflux ratio?

[crackher]

Anyone have any ideas how to accurately measure the reflux ratio? I have aread alot pertaining to the drip/min and off take. but how do I measure the amount returning to the still??? This problem I can't get around. people talk about returning ~3 drips back to the colum for every 1 in off take. that would mean a 3:1 ratio I get that but how you know that you are returning 3 into the column if you cannot see the drips?