St. Paul’s Cathedral

Bischof An obsolete process for making white lead (basic lead carbonate), invented by G. Bischof around 1900. Lead monoxide was reduced by the carbon monoxide in water-gas to form black lead suboxide, oxidized in damp air to lead hydroxide, slurried in dilute acetic acid, and carbonated with carbon dioxide. Piloted in Willsden, London, and commercialized by L. Mond in the Brimsdown White Lead Company. A sample of Bischof s white lead was used by Holman Hunt in his painting Light of the World, now in St. Paul s Cathedral, London. 

Newton proposed a law equivalent to = 0.5 (N4), and confirmed this experimentally by timing the fall of spheres from the dome of St. Paul s Cathedral (N5). However, his explanation was based on ideas which bear little resemblance to current concepts of fluid mechanics. 

St. Paul s Cathedral, London. [Pictor International/ Emissions over Europe estimated by Schopp and colleagues. [From R. F. Wright, T. Larssen, L Comarero,... 

Between 1980 and 1990, j mm of the thickness of the external stone walls of St. Paul s Cathedral in London was dissolved by acidic rainfall. A comer of the building facing a power station dissolved at 10 times the rate of the rest of the building until the station was closed. The power station and other industries that burn coal emit S02, which is a majoi source of acid rain (described in Box 15-1). Loss of heavy industry and laws limiting emissions decreased atmospheric S02 from as high as 100 ppb in the 1970s to 10 ppb in 2000. Correspondingly, only mm of St. Paul s external stone disappeared between 1990 and 2000. 2... 

White Lead Company. A sample of Bischof s white lead was used by William Holman Hunt in his painting The Light of the World, now in St. Paul s Cathedral, London. 

The resistance of copper to corrosion renders copper particularly valuable for water tanks and pipes, cooking utensils, sheathing of ships, etc. It possesses many advantages over lead for the covering of domes and other outdoor structures. It was used in a temple frieze at A1 Ubaid (Plate 1), near the ancient city of Ur of the Chaldees, Abraham s reputed city, some 3000 to 4000 b.c., worked up from sheet copper, and has been used by numerous peoples for like purposes ever since. The dome of the Library of the British Museum, London, dating back to 1857, is the largest copper-covered dome in the world. St Paul s Cathedral is lead-covered Wren would have preferred copper, but his workmen appear to have been unequal to the task (p. 195). Copper possesses... 

Lead is used as sheets for gutters, spouts, etc. As strips for leaded lights , in pipes for water, gas, electric wiring, etc. It was once used a great deal for roofing cathedrals and churches but it was very heavy. Wren used it for the dome of St Paul s Cathedral... 

Sir Christopher Wren, the renowned architect of St Paul s Cathedral in London, attributed the majesty of Gothic architecture to Knights Templar and other Crusaders in bringing back Muslim ideas on science and architecture from the Near East ... 

Sir Christopher Wren was a founding member of the Royal Society and frequented the Invisible College. There are scant records of Freemasonry at this time but Anderson s New Book of Constitutions of 1738 notes Wren, the Master of the London Operative Masons Company was a Grand Master of Freemasonry in 1685." Similarly, John Aubrey, an antiquary and fellow of the Royal Society, recorded that an order initiated Wren in 1691 at St Paul s Cathedral." ... 

The most celebrated naval officer in British history was buried in a crypt in St. Paul s Cathedral, and to this day his likeness stands guard 170 feet above Trafalgar Square from atop Nelson s Column. 

Example 9.3. Calculate the velocity a water balloon 10 cm in diameter would achieve if dropped from the top of St. Paul s cathedral. 

Solution 9.3. Besides experiments conducted by Galileo from the Leaning Tower of Pisa, Newton measured particle terminal velocities by dropping hog bladders from St. Paul s Cathedral. Galileo used his heart beat as a timer In this example, the water balloon is assumed to be spherical (which is probably inaccurate because the balloon will deform to achieve the lowest drag). The... 

St. Paul s Cathedral, London. Scanning electron micrograph of Portland Limestone with white crust. Upper portion of the micrograph is the surface view, and the lower portion is the transverse section showing that the pores are plugged with recrystallized calcite. 

Schaffer (17, p. 21) points out that serious damage to the stone had occurred due to oxidation of iron clamps and dowels at St. Paul s Cathedral. However, in all instances the author of this paper has seen, lead coated iron bars were not rusted. 

Figure 8. St. Paul s Cathedral, London. Lead coated iron pins projecting above the weathered surface. Note that the irons pins have not oxidized and therefore the stone has not suffered disintegration.

TOMLINSON You said you re getting calcite deposits on St. Paul s Cathedral in London. They had tremendous sulfur dioxide problems there. Is is because they have managed to get their stacks higher and why is it that we are not finding calcium sulfate there now ... 

Sir Christopher Wren was trained as an astronomer and dabbled in medicine before recognizing that his future lay in architecture. One is left to ponder what a mind that conceived of St. Paul s Cathedral might have achieved if directed to medical science He is buried under a simple unadorned black marble slab in the cathedral that he had spent 35 years building, and the plaque reads Lectory si monumentum requiris, circumspice ( Reader, if you seek a monument, look around ). 

Limestone is hard and strong. St. Paul s Cathedral in London is built from it. It was completed in 1708. 

Critics described the proposed structure as a vast pile of masonry that they feared would never be removed and would become a permanent mutilation of Hyde Park. Indeed, the committee s malproportioned behemoth would have required the laying of fifteen million bricks and the construction of a dome two hundred feet in diameter, considerably larger than that of St. Paul s Cathedral. The mortar would not have been expected to be dry in time for the opening of the exhibition, then less than a year away. 

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