Gateway to Rust and Ruin — Robert E. Vardeman

Sir Francis Barstow has unlimited funds from the alchemist's dream--he can transmute lead into gold with a special ray confined to a Cornish coal mine. To exhaust generated fumes from the electrical equipment, he uses a strange black portal only a foot in diameter--the portal opens onto an entire new dimension, the World of Rust. Other, larger holes have appeared across the world. The Kaiser uses one to smuggle contraband from the United States into Switzerland in preparation for launching a great war, but he is opposed by a brilliant scientist unwilling to thrust the world into such devastation. To achieve his ends, the scientist explores the Rust World to scavenge technology unavailable anywhere else. Sir Francis, with the lovely French aviatrix Nicole Larouse, find themselves in conflict with the Kaiser, his subjects and those who would use the strange black portals to a different world for their own purposes. As a bonus, the short story "The Transmogrification Ray" detailing Sir Francis' alchemical researches (originally published in the anthology Steampunk'd) is included.