A few suggestions: Harrison's Watch, time zones & Daylight Savings

How about a mechanical watch technology to improve ocean-faring? Sure, the compass helped with navigation, but the sky was enough to give mariners a sense of direction during their travels. But as anyone who's ever read Dava Sobel's milestone book "Longitude" can attest, it was John Harrison's mechanical watch that enabled sailors to determine their longitude. With this information, sailors could determine their exact (at least as exact as maps & technology allowed) location in the world. It literally put them on the map. Compasses merely told them which way they were sailing when it was overcast.

On a related note, I'd like to see time zones -- which could be tied to the linking of a set number of cities via railroad -- and Daylight Savings be incorportated with financial incentives, since they greatly improve economies. To reflect history, the timezone bonus probably should also have astronomy as a prerequisite, since it initially was an astronomer who wired accurate time (for a price) to the railroad companies, which led to standardized time.

Daylight Savings also could give a small boost to agricultural productivity.

There, I've given in to my time fetish.

Well, Daylight Savings Time may be too narrow of an idea to apply to the game. And since most turns represent a full year or more, I don't see how you could gameplay it.

That said, I've been thinking a lot about Longitude lately while working on my new Discovery Mechanic. Frankly, I think Civ 4 needs a "Navigation" tech after Astronomy that incorporates the idea of Longitude. (Navigation: prereqs Astronomy and Scientific Method; ... what it actually does is up for discussion)

The benefits of Daylight Savings aren't necessarily noticed on a day-to-day basis; it's a seasonal effect that increases agricultural productivity and reduces energy consumption (which is why the president extended DSL recently). I'd think it could be incorporated. But I understand where you're coming from.

I agree with you on longitude. Also, I've tried to figure out ways how the game can reflect latitudinal effects, most importantly agricultural bonuses for civilizations that are predominantly E-W oriented (or, perhaps, simply with multiple cities within the same climate zones), since crops would be migrating within a climate zone. It's far easier to transplant a crop from the tropics halfway around the world within the tropics; not so easy when you take a banana tree and plant it outdoors in iceland.

Hmmm, perhaps giving workers the ability to modify an accomodating (i.e. no rice growing on mountains) terrain type into a crop that is growing elsewhere in the civilization at an approximate latitude? To prevent civs from going overboard with this, the time for such cultivation could be considerable.

I suspect, however, this wouldn't be practical except for those playing larger maps.

As a possible counter to that latitudinal bonus, E-W oriented civs (or those that span a predetermined number — or, given different map sizes, percentage — of meridians could be penalized from the period in which the civ becomes modern until it triggers Daylight Savings (which, in my proposal, would happen when all cities are linked by rail).