Don't get me wrong, slavery can be great, but it's only great when whipping smallish cities with granaries that were not otherwise working highly productive tiles.
Hehe, it is true that slavery isn't amazing before granaries, but I still feel it has some uses.
To grow from 1 to 2 Population takes 22
To grow from 2 to 3 Population takes 24
To grow from 3 to 4 Population takes 26
To grow from 4 to 5 Population takes 28
1) Quick barb defense. "OMG barbarian walked out of the one fogged tile and is headed for my corn" is a cry heard in many Civ 4 games. Slavery is a great counter. It is less dramatic on normal where a unit can be built in 2 or 3 turns, but it still works.
In our game, with good fogbusting on our peninsula and normal speed, barbs should not be a problem.
So point to Mabraham against slavery.
2) Whip a monument. If the first thing you build is a warrior or monument, whipping that monument when you grow to size 2 turns 22
into 30
instantly. It also lets you grow to size 2 again on an improved food tile while the worker is busy improving the 2nd tile. You get the monument and border pop sooner rather than later.
3)A new city can quickly create a military unit and a worker if it has a good food tile.
Start the city building a unit while growing to size 2, then switch to a worker at size 2. Use the first worker to improve the food and then chop a forest. When the +20 hammers goes into the city, whip the worker complete using 1 population. The #2 city can have another worker and unit out very fast using this method, and it quickly grow back to size 2.
4)Build granaries the turn after researching them 
5)Whipping at 4 population with a full food bin can also be useful. A 2 pop whip at 27/28 food will reduce the city to size 2 and change the food bin to 27/24 food. The next turn you are size 3 and well on your way to size 4 already thanks to the food overflow. This is mainly useful if the workers are not improving tiles fast enough.
The main thing is, you can have stuff now rather than later. Sometimes such a thing cannot have a hard value assigned to it. How do you quantify an axeman army taking an enemy's capital the turn before they get longbows thanks to slavery?
A good question to ponder is how much natural production a city can have to outshine slavery both before and after granaries. Is it +12
per turn? +16
?
On normal speed, I'd say that any city with production of 20
or greater should not be whipped(
much 
). If you naturally produce a swordsman every other turn, I do not see how whipping can speed that up any. Even with a granary, whipping every 3rd turn to produce 2 military units only speeds up things a tiny bit, and it would not regrow fast.
If you whip every 10 turns, you get an average hammer amount like this:
1pop whip - 3
/turn
2pop whip - 6
/turn
3pop whip - 9
/turn
If you whip every other turn, you get an average hammer amount like this:
1pop whip - 15
/turn
2pop whip - 30
/turn
3pop whip - 45
/turn
Whipping hard is mainly for getting out that shiny new soldier you just teched in huge numbers fast. If you frequently whip settlers and workers, you will not have the economy to support the extra new cities on emperor, and the economy will crash. Then you run into the problem of not having anything to build as any additional units/cities do not help you.
I feel Mabraham is correct that we will not use whipping a great deal in the early game with so many hills to work and a larger than usual happy cap. But I still love having it if it is already researched.
, but somehow I don't think it'll matter much 
).
. I didn't check the sattelite wiew culture screen. Since that AI's scout came at turn 20+ (idk exactly), It shouldn't reveal much anyhow.
