FOR decades, archaeologists have probed for secrets inside the Great Pyramids near Cairo. Using the latest technology, they have searched for unknown chambers, hidden treasures, even the mummy of a pharaoh.
But the use of radar, microgravimeters, and tiny robots in the 4,600-year-old structures continues to spark criticism. This often-vitriolic debate burst open again in recent weeks when a well-known French civil engineer, Jean Kerisel, drilled two holes under the largest and oldest of the three Pyramids, the last remaining wonder of the ancient world.
''I am against anything that will touch the pyramid,'' says Gamal Mokhtar, former head of the Supreme Council of Antiquities in Cairo. ''The Pyramids are not an experimental mouse. The pyramids are something sacred.''
But Bahay Issawi, a geologist and an occasional consultant on the Egyptian monuments, disagrees: ''Nobody would object to using sophisticated techniques in the Pyramids on condition that they don't endanger the rocks of the Pyramids. To say nothing should touch them, this is no way to keep the Pyramids and Sphinx intact.''
After obtaining approval from Egyptian antiquities officials, Mr. Kerisel drilled two holes 4.5 and 6.5 feet long and 1 inch in diameter under the Cheops Pyramid in May, according to Shawk Nakhla, Egypt's director-general of restoration and conservation of antiquities. The report on Kerisel's findings is expected in coming weeks.
Kerisel proposed to drill into the mother rock under Cheops Pyramid to check on cracks that may be increasing the humidity inside the monument. This humidity is dissolving the limestone rocks and the gypsum mortar that holds them together. The massive structure covers 13 acres and stands 450 feet high.
Kerisel worked three days, Dr. Nakhla says, and took samples of the rocks from the holes.
Peeping down holes with a telescope
But other Egyptologists and archaeologists, opposed to Kerisel's drilling, claim he has a hidden agenda and just wants to find an undiscovered chamber in the Cheops Pyramid and become rich and famous. He worked only three hours, they say, drilled 10-foot-long holes, and then peered down them with a telescope to see if there was a chamber.
''If he would say he's looking for a burial chamber, he wouldn't get any permission ... [to work in the Pyramids] so he has to say he is restoring the Pyramids,'' says Zahi Hawass, director of the Giza Plateau, the complex that holds the Giza Pyramids, near Cairo.
Dr. Hawass also says Kerisel lacks an adequate knowledge of the great monuments and their history, and that he should have tried his technique first on a less famous pyramid. But Nakhla defends Kerisel's drilling as a sound conservation technique. ''Boring holes is not destructive,'' he says. ''It is conservation work. Everywhere they are boring holes.'' Scientists use this technique, he adds, to monitor temperature and humidity and to remove humidity by allowing air to circulate.
Venting a Pyramid
Kerisel, who couldn't be reached for comment, has worked on the Pyramids before. In 1989, he measured the pollution and humidity in the Pyramids resulting largely from the hordes of tourists that visit every year. He proposed installing three ventilators in the Cheops Pyramid to increase air circulation. After the ventilators were installed, Nakhla said, the situation clearly improved.
But if Kerisel's goal was to search for other chambers in the Pyramid, as his critics contend, then he is not the first. Archaeologists have hoped to find treasures and maybe even the undiscovered mummy of the great Pharaoh Cheops. This powerful leader, who ruled from 2551 to 2528 BC, was famous for building not only the largest, but also the most perfectly constructed pyramid.
The search for hidden chambers began in the 1960s with a group of scientists from the University of California, Berkeley.
Using radar that allowed them to see through the rock, they searched in the Chepren Pyramid at Giza, which is slightly smaller than Cheops, and found nothing. In 1986 a French mission, using a sounding device known as a microgravimeter, located what appeared to be three cavities, six feet by nine feet, in Cheops. Widespread criticism arose after they later got permission from Egyptian antiquity officials to drill a hole 200 feet long and one inch wide in the Pyramid's wall to photograph a room. They drilled only 10 feet before reaching sand.
In 1992, a German oil-drilling technician sent a four-inch-high robot down Cheops' air shafts. He was ordered to stop work after breaking Egyptian law by announcing publicly that he had found a door and metal piece before he had consulted with Egyptian officials.
As long as the mystery of what lies inside the great Giza Pyramids remains, there will be people wanting to solve it. And as long as the Pyramids are standing, attempts will continue to preserve them for eternity. That is why some experts are demanding greater caution be taken to discern experienced restorers from amateurs and safe technologies from harmful.
Egyptologists opposed to Kerisel's drilling claim he has a hidden agenda - to find an undiscovered treasure chamber.