in the early summer of 1886. The next year Benz created the Motorwagen Model 2 which had several modifications, and in 1887, the definitive Model 3 with wooden wheels was introduced, showing at the Paris Expo the same year. Benz began to sell the vehicle (advertising it as the Benz Patent Motorwagen) in the late summer of 1888, making it the first commercially available automobile in history. 1885–1887: William Stanley, Jr. of Brooklyn, New York, an employee of George Westinghouse, creates an improved transformer. Westinghouse had bought the patents of Lucien Gaulard and John Dixon Gibbs on the subject, and had purchased an option on the designs of Károly Zipernowsky, Ottó Bláthy and Miksa Déri. He entrusted engineer Stanley with the building of a device for commercial use. Stanley's first patented design was for induction coils with single cores of soft iron and adjustable gaps to regulate the EMF present in the secondary winding. This design was first used commercially in 1886. But Westinghouse soon had his team working on a design whose core comprised a stack of thin "E-shaped" iron plates, separated individually or in pairs by thin sheets of paper or other insulating material. Prewound copper coils could then be slid into place, and straight iron plates laid in to create a closed magnetic circuit. Westinghouse applied for a patent for the new design in December 1886; it was granted in July 1887. 1885–1889: , a French inventor, builds two small electric submarines. The first Goubet model was 16-feet long and weighed 2 tons. "She used accumulators (storage batteries which operated an Edison-type dynamo." While among the earliest submarines to successfully make use of electric power, she proved to have a severe flaw. She could not stay at a stable depth, set by the operator. The improved Goubet II was introduced in 1889. This version could transport a 2-man crew and had "an attractive interior". More stable than her predecessor, though still unable to stay at a set depth. 1885–1887: Thorsten Nordenfelt of Örby, Uppsala Municipality, Sweden produces a series of steam powered submarines. The first was the Nordenfelt I, a 56 tonne, 19.5 metre long vessel similar to George Garrett's ill-fated Resurgam (1879), with a range of 240 kilometres and armed with a single torpedo and a 25.4 mm machine gun. It was manufactured by Bolinders in Stockholm in 1884–1885. Like the Resurgam, it operated on the