C O N T E X T 1 1 0 : J U LY 2 0 0 9 7 Patent Victoria stone The photograph shows paving at Clapham North station. This is one of the last places on the London Underground network where patent Victoria stone can still be seen, although it was once quite widespread. There are a few chips and cracks, and the surface is evenly worn and polished, but it has managed to withstand one of the most severe pedestrian environments any paving material can be subjected to, with almost no maintenance at all since being first laid in 1900. The Patent Victoria Stone Company manufactured paving slabs, window sills, stair treads, sanitary ware and other precast items at its works at Groby Quarry, near Leicester, through much of the second half of the 19th century, up to the first world war, and possibly for a few years after. It was wound up in 1927. The material was manufactured in two stages. First, high-quality cement (originally imported from Germany, as English material was at the time inferior) was mixed with finely ground granite, and cast in moulds to the required shape. After the initial cement set had taken place, the various items were steeped in tanks of a saturated sodium silicate solution for seven to eight weeks before finally being washed, dried out and transported to the customer. The second stage is of particular significance, as it acted on the free lime resulting from the original hydration of the cement (forming the calcium silicate hydrate binder) to turn it into yet more calcium silicate, thus increasing the most durable binder component, and sodium carbonate, which is soluble, and could be washed away. Chemically, the result is a true artificial sandstone, rather than a concrete as currently understood. The material has a very unusual mix of qualities, being extremely dense, durable, homogeneous and resistant to wear, while being aesthetically much more pleasant than most equivalent modern concretes. For many years within London Underground it was assumed to beYork stone paving (which it does resemble in many ways), although the addition of perhaps one slab on each platform with cast-in bronze letters giving the company name told close observers that something else was going on. Unfortunately, at Clapham North this name slab seems to have been covered by a large piece of operating equipment, but one can hope that it still exists, even if currently inaccessible. Because it is under-recognised, much patent Victoria stone has been lost, and what little remains is irreplaceable. Its cultural significance as a particularly interesting product of its era really needs to be properly established so that what remains can be preserved and understood for the remarkable material that it is. I am at present researching patent Victoria and other early artificial stones in more detail, and would be very grateful indeed if IHBC members could let me know if they might be aware of any, so that I can compile a gazetteer of examples and possibly carry out some tests (small samples for destructive laboratory testing would be particularly valuable). Broadly speaking, if you know of a dense, cast material which does not appear to be either stone or concrete, but might be either, and dates between, say, 1860 and 1920, it may well be of interest, particularly if it is in a public or institutional building such as a station, asylum or hospital. Digital photos by email with locations will be very welcome indeed. I can be contacted through Julian Bagg, coordinator of the IHBC technical panel at technical@ihbc.org.uk Ian Brocklebank Material matters Letters ‘Temple’ is a mosque From Malcolm Lake, Omagh I write in response to Peter Arnold’s letter (‘Baha’i wear and tear’, Context 108, March) that followed from the announcement of the Bahá’í Holy Places in Israel having been givenWorld Heritage Site status by UNESCO. Arnold seems to have his faiths mixed up. There is no Bahá’í Temple inWilkes Barre: it is a mosque. There are seven existing Bahá’í Houses of Worship in the world: in North America, Germany, Panama,Western Samoa, Africa, Australia and India. They relate to continents and island groups. I would in particular refer to two of these buildings: the ‘Mother Temple of theWest’ (dedicated 1953) is in Evanston (Wilmette), Illinois, at the end of The Loop, the overhead railway that serves Chicago. It employed sculpted, pre-cast, no-fines concrete panels and the brushed aggregate in the mix makes it shine brilliantly. The Indian Temple (dedicated 1986) near New Delhi, made up of nine in-situ concrete petals, is modelled on and inspired by the Lotus flower. The petals are faced in marble. It is a testament to the Indian construction industry that the building was completed on time and on budget. Because of the extremes of heat, ice was used in the water for the concrete mix. The petals were handpoured for a continuous 36 hours. Malcolm Lake
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