Place the sliced peaches in a large bowl, and sprinkle with lemon juice. Mix gently. In a separate bowl, mix together the flour, sugar, cinnamon, nutmeg and salt. Pour over the peaches, and mix gently. Pour into the pie crust, and dot with butter. Cover with the other pie crust, and fold the edges under. Flute the edges to seal or press the edges with the tines of a fork dipped in egg. Brush the remaining egg over the top crust. Cut several slits in the top crust to vent steam.