Over our prow, the back wall of the huge container ship towers dramatically, the words "DIXIE MONARCH" painted in bold white letters over the smaller word "PANAMA." Sailors appear at the railing high above and a few minutes' work secures the two boats together by means of huge ropes, cleated and tied, the sturdy winches on our foredeck pulling the lines tight. Like an ant taking charge of a boulder, our tiny craft is now in control of the 656 foot monster before us, and we are ready to go.

I'm sitting aft on the deck of the M/V Unidad, a tugboat owned and operated by the Panama Canal Commission, one of 17 in their fleet. Under the clarity of a tropical morning sky we begin our transit, pushing the Dixie Monarch toward the Miraflores Lock, her first step in the Pacific-Atlantic passage across the lushly jungled isthmus. Our progress is so gradual, it's almost hard to believe we're even moving. The monarch, laden with stacks of containers of unknown content and origin, is a heavy ship to guide and the canal is a delicate path for such a huge boat to navigate; slow, caution, painfully deliberate progress must be the rule.

So that half an hour later, seemingly without having made any headway at all, I make my way to the bridge, to press the captain with questions and listen to him tell stories. Transits, statistics, navigation, wrecks. "In 1978," he recounts, "went down a boat called Sai Yong. Asian boat. Full of rice. Ran aground an island in the lake. Big mess. She was an old boat, and when they try to pull her up she break some more. Rice everywhere, They had to bring in dredging boats to clear out all the rice."

On and on the information pours out of this man, its flow attenuated only by the wide valve of almost perfectly mastered English. Captain Davis has worked on Canal tugs for 32 years, and he knows all about slow-paced living. He comfortably sips his coffee between sentences, at ease with time, practiced at patience, while slowly, so slowly, our tug and another at the huge ship's bow carefully position their enormous charge for the trip through the lock which, deceptively close, inches towards us, a distortion of any usual relationship between distance and time.

But progress is progress, even when the human eye operates on a scale too quick to detect it. And as the Dixie Monarch slides into place within the broad opening to the lock, locomotive engines looking as stout and powerful as our own boat chug into place around her, two in front, two astern, left and right, firmly gripping the iron rails which run along the cement boundaries of the lock. Again we watch the ritual of railings and ropes, until everything is tight and secure, and now with only slightly greater speed all assembled, two tugs, four locomotives, and the massive Dixie Monarch herself are drawn into the narrow concrete passage for the vertical transition to the level of the lakes in the center of the land. It is an incredibly tight fit. Without the tugs to keep her steady and the trains to keep her centered, there is no way such an enormous boat could hope to hit such a small target. As it is, barely two feet of space borders her on each side. But finally, we're in.

The initial phase of the journey is complete, and all engines come to a stop. Behind us, strong iron gates swing closed, sealing us in, and for a moment, there is calm. But then, incredibly, the water around churns to a froth. It wells up from below, fed from the lake above through a series of valves, pushing us up in a tremendous act of hydraulic levitation, lifting the unliftable 12 meters above the sea level at which we entered. And like a sun rising over the lock wall, the control center comes into view, proudly displaying in capital iron letters, "MIRAFLORES LOCK, PANAMA CANAL, 1913."

This entire project, so ingeniously designed, seems to benefit from the lack of technology available during its design and construction, in that since the entire mechanism is powered solely by the weight of the water itself, no electricityãat allãis required for its operation. The valves are opened and shut by hand, and the rest is left up to gravity, water seeking its own level, and being carefully controlled in the process. It will get its wish, eventually flowing out into the sea, but not before it helps one ship up the steps and another down in a beautifully orchestrated exchange of force for freedom.

Above the gates aft the Pacific Ocean once again comes into view, revealing a long queue of boats patiently waiting their turn, while in front the gates swing open, and our forward trip resumes. We make our way a short distance to the lock's second stage where we are lifted a further 11 meters into the sky, this time before the snapping cameras of the tourist center's observation platform, and from there, the locomotives see us safely to the end of the lock. There they retract their cables and prepare for the next boat's transit, and we chug along our way, steadily pushing the huge boat before us into the comparatively wide reaches of Miraflores lake.

At the end of this small reservoir lies the Pedro Miguel Lock, a single-chambered step which will elevate us another 12 meters, but for the moment we're just cruising, surrounded by riotous walls of arching palm and hairy vine, a tranquil moment in the midst of the world's busiest waterway.

The slow power of the boats, so gracefully nosing and nudging each other, bumping and dancing their way across the lake, is dwarfed by the infinitely slower, infinitely more powerful grace of the land itself, making of the whole transit, powered by the weight of the earth and cut through the density of the jungle, something majestic, a stately procession enabled by ingenuity but dependent upon the generous battery of the planet, in a tempo which almost obscures the fact of the entire process as a time-saving convenience.

But soon enough we arrive at the lock, and soon again after, push our way through the forward gates into the waters of the Gaillard Cut. The 7 mile trench, the most difficult and dangerous part of the canal to construct, represents more hard labor than I even care to, or can, imagine, the toil of thousands in the Panama heat, armed with picks and shovels, cutting by hand a gauge in the earth sufficient for the passage of a Titanic. It's a straight shot across the jungle, a deep laceration cleanly made, and neatly healed. But as our progress continues I see them reopening the wound, a canal-widening project to allow more traffic and create more jobs. Now they're using earth-moving machines, Caterpillars and tractors, but still it looks a daunting task, the formidable jungle reluctant to suffer further encroachment.

Ultimately, we reach the end of the cut, and the small port of Gamboa. Ahead, the expanse of lake Gatun, 85 feet above sea level, flattens out before us, dotted with islands and ships, but its inviting waters are not for us; our work ends here at Gamboa. We've come 25 miles in just over four hours, and as the cut widens to the lake, sailors again appear at the rails, the thick ropes are drawn in and coiled, and solo again under her own power and navigation the Dixie Monarch lumbers off across the vastness of the lake to meet another set of tugs at the Gatun Locks on the other side. We pull up to the Gamboa dock to await another ship, to tie ourselves to her and escort her, to steady her course on the remainder of her incredible journey from one great ocean to another, and then, to watch as she charges out into the Pacific, bound for some faroff port.