John Gilmer wrote:

... A 10" diameter globe would only take a 15 watt CF. In theory
that's as bright as a 60 watt conventional light but who is kidding!

It's close. You can measure the relative outputs with a Bunsen grease spot
photometer. Put a bulb at each end of a yardstick and move a piece of white
paper with a grease spot between them until the spot disappears, indicating
equal illumination from both sides, at which point I1/d1^2 = I2/d2^2 for
distances d1 and d2 from bulbs 1 and 2.

Nick