`SECRETS' SOLID AS STONEHENGE.

Byline: John Levesque Seattle Post-Intelligencer

If the builders of Stonehenge whistled while they worked, they probably whistled the Stone Age equivalent of ``If I Had a Hammer.'' And a chisel. And a cordless drill. And maybe a backhoe.

How they managed to drag stones the size of buses over hill, dale and gully about 25 miles to a plateau in what is now southern England, then erect them in a remarkably precise solar alignment, is astounding even after watching ``Stonehenge,'' the first installment of ``Secrets of Lost Empires.''

No one is quite sure how Stonehenge and other such marvels of engineering were constructed. But buoyed by the acclaim that ``This Old Pyramid'' received in 1992, the people who produce ``Nova'' at WGBH in Boston decided to see if they could replicate such feats, using only volunteer labor and the tools available to the ancients.

As it turned out, none of the four segments of ``Secrets of Lost Empires'' was able to hew to that requirement, usually for reasons of time, sometimes for reasons of safety. Thus we have bulldozers helping out in Africa for ``Obelisk''; iron hammers and chisels helping out in South America for ``Inca''; steel bracketing helping out in Europe for ``Colosseum''; and modern scaffolding helping out in England for ``Stonehenge.''

Still, the four hourlong segments of this ``Nova'' special are praiseworthy for their enthusiasm and almost childlike wonder in approaching intriguing topics. The grudging reliance on 20th-century implements notwithstanding, each segment succeeds in offering reasonable - and not-so-reasonable - explanations for how some amazing things got built.

This will come as no surprise to regular viewers of ``Nova,'' now in its 23rd season of making science scintillating. But perhaps because ``Nova'' is as old as some artifacts in my garage, it is worth noting that ``Secrets of Lost Empires'' is fresh and spirited and, at times, even a little contentious.

In addition to figuring out how Stonehenge was built, the ``Nova'' special tries to answer questions about how the Egyptians carved and erected the towering 400-ton obelisks that replaced pyramids as monuments to the Pharaohs; how Inca craftsmen built temples and fortresses out of immense jigsaw-piece stones fitted so precisely that no mortar was needed; and how the Romans erected a huge awning over the bleachers of the Colosseum.

Even with modern tools and rigging, some of the tasks are daunting. A granite sculpture, for example, is always subject to fracture during installation, yet the Egyptians of 3,500 years ago had only levers, ramps, ropes and muscle to transport obelisks from quarry to installation site, sometimes several hundred miles.

About 1,000 years earlier, the builders of Stonehenge had even cruder implements, yet the lintels that rest atop the huge vertical uprights were fixed in place using mortise-and-tenon joinery. Incredible!

The accomplishments of all of these ancient engineers and builders, some of whom had no codified mathematics, are astonishing, to be sure. But when viewed from a high-tech perch on the cusp of the 21st century, they actually are quite humbling.

THE FACTS

The show: ``Nova: Secrets of Lost Empires.''

When: 8-10 p.m. tonight, continuing 8-10 p.m. Wednesday.

Where: KCET (Channel 28).