Updated 11-I-2014


The Dalston factory of Siemens Bros. was established in 1908, and holds special significance as being the first factory in Britain to produce metal filament lamps - at first being based on Tantalum. Soon afterwards it was converted to produce the more efficient tungsten filament lamps. Despite its pioneering role in the early days, Dalston relied entirely on German technology and the severing of all links between Siemens UK and Germany at the outset of WW1 meant that the British factories quickly fell behind. Having no laboratories of its own Daltson's products quickly became obsolete, and in 1923 the factory was closed down.
Factory Buildings, believed to have been photographed in 1908

Address 28 Tyssen Street, Dalston, London
Location 51.546809°E, -0.072419°N
Opened 1908
Closed 1923
Products Incandescent Tantalum filament & tungsten filament lamps.

The Tantalum Era
The German company founded as Siemens & Halske has a long history in the UK, stretching back to 1858 when Werner Siemens sent his brother William to London to establish an overseas sales operation. Manufacturing soon followed in 1863 when a factory was opened in Woolwich to produce electrical cables. On account of the strong national interests in buying British products at the time, steps were taken to make the company appear as British as possible. By 1888 the British operations were re-named Siemens Brothers and became a separate entity from the German parent, but Siemens & Halske still maintained a substantial shareholding.

Until the early 1900s all incandescent lamps were made with carbon filaments, a material which by today's standards is very inefficient. They could attain an efficacy of only 3-4 lumens per Watt. The incandescent lamp industry was dramatically shaken up in 1905, when Dr. Werner von Bolton and Dr. Otto Feuerlein of the Siemens & Halske works in Berlin completed their development of the tantalum filament lamp, which at once allowed efficacy to be almost doubled to 6 lm/W. Siemens' lampmaking operations had until then been restricted almost exclusively to Germany, but the invention of the Tantalum lamp was to shape in very great measure the future of that company as a powerful international force. On 10th February 1906 Siemens' activities were extended to the Americas, by selling for $ 250,000 the rights to the manufacture of its tantalum lamps to General Electric of USA. Additionally, GE was to pay a hefty royalty on each lamp sold and had to purchase the tantalum wire from Siemens' own operations in Berlin. Meanwhile in the European markets Siemens took advantage of its technical strength by founding its own tantalum lamp factories, and this resulted in the opening of the Dalston factory, East London, in 1908.

The Tungsten Era
Siemens' strengths in tantalum were to be short-lived however. The discovery that tantalum could make suitable filament materials encouraged other researchers to experiment with different metals, and intense research was ongoing particularly in Germany of the Osmium filament lamp, and in Austria and Hungary on the development of tungsten, both of which offered still higher potential. The tungsten lamp could also solve another drawback of tantalum in that the former could only be operated on DC circuits, whereas AC was of course the primary supply source. Progress was quick and by the end of 1906 it was made clear that tungsten would eventually displace tantalum due to the fact that GE made an even more expensive deal with the four leading Austro-Hungarian and German pioneers, to secure the exclusive American rights to the tungsten lamp for an even more expensive fee of $ 1.25 million. Although the tungsten lamp became commercially available in 1907 and it was indeed superior to Siemens' Tantalum lamps, it was at first far more expensive and more difficult to manufacture. It was not until GE developed its own superior tungsten lamp in 1910, based on drawn metal wires rather than the squirted and sintered wires of the European pioneers, that the tungsten lamp became more cost-effective and could displace tantalum.

As a result the shoe was then on the other foot for Siemens - having profited for only a very brief period with its Tantalum lamps, it then had to license the use of GE's drawn tungsten patents to remain cost competitive, and turn over its own factories to adopt the newer technology. Consequently in 1911, shortly after the German operations, Dalston was converted to the manufacture of tungsten lamps.

Separation from Siemens & Halske
The fortunes of Siemens were to take a further and catastrophic downward turn with the outbreak of World War 1, when many of its overseas assets were confiscated. On 14th August 1914 Siemens UK operations including the Dalston lampworks were seized by the Custodian of Enemy Property. From this time onwards, the British Siemens factories had no further link with Germany, which was to prove a tremendous setback because Siemens had kept all of its technology and research operations in Germany, and the overseas factories had no technical competence of their own. In the fast-moving world of electric lamps where technologies are changing every few years to make lamps cheaper and more efficient, Dalston was quickly left behind. The UK Government eventually found a buyer for Siemens Bros in 1917 when the entire group was sold to C. Birch Crisp & Co., a finacial syndicate from London. In 1919 Birch Crisp disposed of the company to English Electric Ltd.

Around the same time English Electric had merged with Dick Kerr & Co, a similarly vast electrical engineering company, and Dick Kerr had its own lampworks at Preston. The result of the mergers was that the lampmaking operations of English Electric at Dalston and Preston were combined, forming the new company Siemens & English Electric Lamps Ltd. In 1921-22 this new company entered negotiations with Anton Philips of the Netherlands, who was desperate to get a foothold into the British lamps business and had a keen interest in purchasing it. However no deal was reached.

Following the amalgamation of the two companies, it quickly became clear that without any laboratories or technical capability of its own, the Dalston lampworks was the weaker of the two partners. This resulted in its closure in 1923, with all lampmaking of the group being concentrated at Preston.

Factory Movie
A marvellous insight into the factory operations survives in the form of a film made by British Pathe. Tantalum lamps are clearly visible in several production stages, for instance the filament mounting operation which clearly shows two-tier squirrel cage filament mounts, a type which were only ever produced for tantalum lamps. Owing to the fact that the factory was converted to Tungsten lamps in 1911, the date of this film can therefore be placed at 1908-1911.

Examples of Dalston Lamps

Tantalum Globe Tantalum Double Cage

1 Siemens Brothers 1858-1958, J.D. Scott, Weidenfeld & Nicholson 1958, pp. 153 & 201.
3 Death of a Lightbulb, J. Otten, Blue Ocean Publishing 2012, p.34.