Article taken from "Backsights" Magazine published by Surveyors Historical Society

Reprinted from The Washington Daily News, April 15, 1953.

YOU CAN’T BUILD THAT MOSQUE WITH A COMPASS

The Mosque on Massachusetts Avenue [in Washington D.C.] faces 56 degrees, 33 minutes, and 15 seconds east of true north, and thereby hangs a minor tale.

The direction is toward Mecca, which all mosques must face with mathematical exactness. It was calculated for this mosque by the Egyptian Ministry of Works in Cairo. Egypt is one of the Moslem countries sponsoring the mosque. The Egyptian Ambassador is president of the organization building it.

Passersby - many of them Moslems - keep dropping in, and some of them have come up with a frightening thought. The direction 56-33-15, they pointed out, was slightly north of east. But Mecca, the Moslem holy city in Arabia, was south of Washington. (Washington - 38 degrees, 55 minutes. Mecca - 21 degrees, 25 minutes). Take any map, they said, and draw a straight line between the two cities and the line would go slightly south. But the mosque pointed slightly north.

The trouble was easily explained. The visiting Moslems had been thinking in terms of the standard Mercator projection map. On such a map the straight line would go slightly south, but it would not be the shortest distance to Mecca. The shortest distance, as an air age knows, would be a great circle route, easily seen on a globe or a special flat map called a ‘gnomic projection’, heading slightly north to start with, passing near New York, Halifax, and along the North Atlantic iceberg lanes on its way across the world. It was like the great circle route suddenly coming to the Moslem world - except, of course, that Moslems drawing circles in the sand centuries ago had known about it all along.

Then there was the disturbing day when Egyptian Ambassador Mohammed Kamil Abdue Rahim visited the mosque. He stood in the center of the great, half-completed structure with a pocket compass in his hand. He stared and shook his head and said: "It points so far north."

Architect Irwin S. Porter said he explained to the Ambassador that the compass pointed toward the false magnetic north and has - among other things - a seven-degree westerly variation error in it."

Even so, the Ambassador began telling the architect a little story. In Egypt when they build a mosque, the story went, they gave the builders a point to sight on. Then when the building was done, the royal engineers came out and surveyed. And if it wasn’t right, the builders had to tear the whole works down and build it again.

"I’ll tell you, it gave me a few nights of worry," Mr. Porter said.

Mr. Porter called up a cartographer, Wellman Chamberlin, of the National Geographic Society, and asked him "just for formality" to check the direction of Mecca.

"He called back in a few hours," Mr. Porter said, "and of course it was right - 56-33-15."

Mr. Porter asked the cartographer: "But how can I explain this to the Ambassador?"

"Tell him to take a globe," was the cartographer’s advice, "and two thumb tacks, one at Washington and one at Mecca, and to run a string between and he will see that that is the direction of Mecca."

Mr. Porter’s own office made up the globe with the tacks and string and sent it to the Ambassador.

"The Ambassador now is very happy," said Mr. Porter.

The News called the embassy and brought up the general subject with the third secretary.

"Well, the direction is 56 degrees, 33 minutes, and 15 seconds," said the third secretary. "It was calculated by the Egyptian Ministry of Works in Cairo. There can be no dispute about it."

"It’s very simple," he went on, "Anyone can demonstrate it. Just take a globe and two thumb tacks and ...."