Bring a kettle of water to a boil and have ready a large bowl of ice and cold water. Add corn to boiling water and simmer 4 minutes. With tongs transfer corn to ice water to stop cooking. When corn is cool enough to handle, drain and cut corn kernels from cobs. Cut bacon into 1/8-inch-thick strips. In a heavy skillet cook bacon over moderate heat, stirring occasionally, until browned and transfer to paper towels to drain. Thinly slice enough scallions crosswise to measure 1 cup. In a 3 quart heavy saucepan simmer cream, water, and lemon juice with bacon, scallions, and butter, stirring, 1 minute. Add corn and pepper and salt to taste and cook until liquid is slightly thickened, about 5 minutes.