Bowling Green, Va. ? Succeeding on his third try to visit them, President Bush comforted thousands of Boy Scouts on Sunday at a national jamboree marred by the electrocutions of four leaders and stifling heat that sickened 300.

“The men you lost were models of good citizenship,” Bush told the estimated 50,000 Scouts, leaders and visitors attending the event near Bowling Green, Va.

“As Scout leaders, they devoted themselves to helping young men develop the character and skills they need to realize their dreams. These men will always be remembered for their leadership and kindness, and you Scouts honor them by living up to the ideals of the Scouting they served.”

Bush told the crowd that the first man he often sees every morning, chief of staff Andy Card, is a former Scout from Massachusetts; Vice President Dick Cheney was a Boy Scout in Wyoming; and Defense Secretary Donald Rumsfeld was an Eagle Scout in Illinois.

Bush’s speech was about patriotism, community and military service to the nation, but he also recalled how his mother, former first lady Barbara Bush, was the den mother of his troop. “It’s about the time her hair turned white,” he joked.

President Bush addresses the National Scout Jamboree at Fort A.P. Hill in Virginia. Bush helped commemorate the four Scout leaders killed last Monday at the Jamboree when the tent they were helping erect touched powerlines overhead.

It was Bush’s third attempt to travel to Fort A.P. Hill, the Army base hosting the Jamboree where Scouts are trying to end their 10-day gathering with cheery memories of mountain biking, fishing, scuba diving and trading patches with newfound Scouting friends .

On Wednesday, Scouts waited hours in the heat for Bush, who later canceled his appearance because of threatening storms. Scouts began collapsing from high humidity and temperatures in the high 90s. More than 300 people were treated for heat-related illnesses.

Bush’s second attempt to visit the Jamboree was postponed from Thursday at the Scouts’ request. Officials wanted to review safety procedures for large crowds and replenish water and other supplies.

The illnesses came as the Jamboree participants were still trying to overcome the deaths last Monday of four adult Scout leaders who were electrocuted in front of several Scouts when a metal pole at the center of a large dining tent touched power lines.

The day before, a volunteer died of an apparent heart attack.

The weather was considerably cooler Sunday, but Scout officials took extra precautions. Air-conditioned buses served as cooling stations, there were more tents to provide shade, stretchers were spaced out over the field in case they were needed, and cases of bottled water dotted the lawn of the arena.

Even so, the day was not without incident. A military helicopter carrying several photographers for the Scouts made an emergency landing after its engine failed Sunday afternoon.