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formerly the Electric Vehicle Co
1914. The Mechanical and General Inventions Co is listed in the phone book at 15-16 Cockspur Street. The company becomes increasingly focussed on the aeronautic business.
16 February 1914. The Mechanical and General Inventions Co signs an agreement with Albatroswerke. The German company sends a biplane to Britain for trials. If the trials are satisfactory, the plan is for the Mechanical and General Inventions company to become sole UK agents for the plane and to manufacture it in Britain under licence.
April 1914. The Albatros plane impresses experts at the Hendon air show. Albatroswerke has doubts about the wisdom of letting Lehwess have a military plane and asks him to return it. Lehwess refuses. Albatroswerke sues for the return of its plane. The case is still pending when war breaks out.
5 August 1914. Mechanical and General Inventions writes to the British government offering to let them have the plane for £1,850. At a meeting between Lehwess and Sefton Brancker, of the Royal Flying Corps, Mechanical and General Inventions agree to hand over the plane, leaving the question of payment to be sorted out later.
1915. The Mechanical and General Inventions Co is now listed in the phone book at 11 Long Acre, Covent Garden.
3 May 1918. The Official Receivers starts proceedings to wind up the Mechanical and General Inventions Co, of Whitehall House, Charing Cross.
1918-1922. Protracted legal proceedings to wind up the company under the Trading with the Enemy Act. According to the Board of Trade Lehwess, a German national, “completely controlled the business and the operations of the company.” 
1925. Mechanical and General Inventions Co now listed in the phone book at 10 Charles Street.
May 1925. Mechanical and General Inventions Co now handles the controlograph, an early form of tachograph.
November 1925. Mechanical and General Inventions takes a stand at the Olympia Motor Show to publicise the controlograph.
1926. Mechanical and General Inventions Co. claims payment from the British government for the Albatros biplane. The government is reluctant to pay up, especially as Lehwess had never paid for the plane in the first place. The government eventually agrees to pay £800.
During this period the Mechanical and General Inventions Co. is closely associated with several other British and French companies, including: MAGIC Ltd, France, Controlograph (London) Ltd, Le Controlograph, of 97 Boulevard Gouvion St Cyr, Paris, SA de Brevets Solcar Aerable Monobloc, 234 Boulevard Pereire, Paris, which became Omnium Financier pour L’Industrie et le Commerce, and in 1935 Solcar Sunshine Roof Patents.
1933. The Mechanical and General Inventions Co and Lehwess start a patent dispute over a sunshine roof with the Austin Motor Co and Sir Herbert Austin. The High Court agrees that Austin had pirated the idea and awarded Lehwess and the Mechanical and General Inventions Co £98,550. The award was overturned on appeal but the House of Lords partially reversed this decision, awarding the Mechanical and General Inventions Co and Lehwess £35,000 in March 1935.
26 July 1935. Arthur Riding, secretary of the Mechanical and General Inventions Co, writes to Scotland Yard saying the controlograph could help the police to enforce the newly reintroduced speed limits. Riding was formerly secretary of the London Electrobus Co.
31 March 1944. William Overton and the Mechanical and General Inventions Co apply to extend the patent for the “solcar” form of sunshine roof.
15 November 1968. The company was struck off.