This is the climate that tries the soul, when the faint of heart retire to shore and mountain and the August streets and corridors of the nation's capital wilt in steamy near emptiness. But some summer soldiers labor on. Today's dispatch from the front.

As a long row of sunflowers drooped outside the window, their petals contorted by the heat, Mary McLean Bancroft took out a blank Rolodex card and wrote, "Interior Department, Secretary: Cecil Andrus. 343-3171, 343-7531."

She put the pen down, inserted the completed card into the file in case her boss wanted to call one of the Cabinet secretaries and picked up another card. Agriculture Department," she wrote.

"Secretary: Bob Bergland . . ."

While Republican presidential candidate George Bush spent the day studying issues in Kennebunkport Maine, two dozen of his compaign workers hunched over their desks in Alexandria, clipping papers, writing down telephone numbers and returning phone calls.

The high Temperature in Portland, Maine, not far from Kennebunkport, was 70 degrees yesterday, according to the National Weather Service. In Alexandria, however, the mercury had reached 94 degrees by midafternoon.

"When you work on the Hill, if it gets too bad in August you can take comp time and get out of here," sighed campaign aide David Sparks.

"But this is a campaign. It has a rhythm. You just can't leave now."

On the third floor of their brick office building off Route 1, Pete Teeley returned from lunch with a political columnist to find a pile of pink telephone message slips waiting for his attention.

Teeley, a senior aide, spread them out in front of him, picked up the phone and started pushing the buttons.

"How are things going in Massachusetts? .... Yeah .... Mm-hm ... How are the Red Sox doing? .... Oh, that's right, I forgot about the Orioles . . ." Two more minutes of talk and Teeley said, "Okay, thanks," then pushed another button and called another number.

Across his forehead, his hair formed tiny wet curls.

Next door, in strategist David Keene's office, the wall was covered with a large map of the United States, complete with blue and yellow pins denoting the presence of compaign aides or offices. Large stretches of the map remained pinless.

"The heart's worse when you're bored," said campaign press aside Susan Morrison, who left a job with the Democratic National Committee to join the Bush campaign in Aprils. "But in a campaign like this, August isn't a time when you're going to be bored."

"You do lose some people in the summertime" said July McClennan, who had ventured up from her office two flights down. The air conditioning was working better down there. "i don't know if it slows things down any for us. It just means a bigger workload for everyone else."

Down the hall a soft drink machine doled out cold bottles to thirsty staffers. the steady "thunk" of quarters, marking a completed transaction, could be heard up and down the halls all afternoon.

"People aren't just drinking They're putting their faces up against the thing to cool off," said Mary All, who refused to be cowed by the weather.

"You get so engrossed you're able to turn off any thoughts about the heat . . . unless the air conditioning goes on the fritz again."

McClennan was a trifle more subdued. "Anyone who has any sanity who's lived in Washington for a while wants to leave in August," she signed.

"Then why are you here?" a visitor asked.

"I am here to get George Bush to the White House," she said, accompanying her ringing statement with a small smile.

"And then, by God," Morrison chimed in, "It's not going to be 78 degrees inside anymore." CAPTION: Picture, Workers for George Bush endure heat for the sake of the campaign. By Ellsworth Davis -- The Washington Post