Get swept away by The Startling Testimony of Plumb Lines below, and buy it outright from Gilead Media on April 1.
|
|
You don't come across an experimental, improvised ambient supergroup every day, but that's exactly what's afoot with Gilead Media's latest release, The Startling Testimony of Plumb Lines.
|
|
The chorobates, described by Vitruvius in Book VIII of the De architectura, was used to measure horizontal planes and was especially important in the construction of aqueducts. Similar to modern spirit levels, the chorobates consisted of a beam of wood 6 m in length held by two supporting legs and equipped with two plumb lines at each end. The legs were joined to the beam by two diagonal rods with carved notches. If the notches corresponding to the plumb lines matched on both sides, it showed that the beam was level.
|
|
Philbin, p. 128Cotterell, pp. 59–61 Another Egyptian method of determining the time during the night was using plumb-lines called merkhets. In use since at least 600 BC, two of these instruments were aligned with Polaris, the north pole star, to create a north–south meridian.
|
|
At around the time of this conference, scientists were making measurements to determine the deflection of the vertical on a large scale. One might expect that plumb lines set up in various locations, if extended downward, would all pass through a single point, the centre of the Earth, but this is not the case, primarily due to the Earth being an ellipsoid, not a sphere. The downward extended plumb lines don't even all intersect the rotation axis of the Earth; this much smaller effect is due to the uneven distribution of the Earth's mass. To make computations feasible, scientists defined ellipsoids of revolution; a given ellipsoid would be a good compromise for measurements in a given area, such as a country or continent.
|
|
Using plumb-lines called merkhets, the Egyptians could calculate time at night, provided the stars were visible. Used since at least 600 BCE, two of these instruments were aligned with Polaris, the North pole star, creating a north-south meridian. By observing certain stars as they crossed the line created with the merkhets, they could accurately gauge time.
|
|
To keep the shafts to the correct alignment, plumb lines were used. Four steel lines, evenly spaced, were suspended around the inside of each shaft, all the way to the bottom. The colliery began production in April 1965. During planning and building the surface infrastructure for the new colliery, employment of 3,000 mineworkers was expected at completion.
|
|
Ancient Egyptian sundial (c. 1500 BC), from the Valley of the Kings, used for measuring work hour. Daytime divided into 12 parts. The Luxor Obelisk in Place de la Concorde, Paris, France The ancient Egyptians were one of the first cultures to widely divide days into generally agreed-upon equal parts, using early timekeeping devices such as sundials, shadow clocks, and merkhets (plumb-lines used by early astronomers).
|
|
The painting shows much of the details of the inscriptions on the disk and half disk, which make up the top of this particular kind of torquetum. A 14th century instrument, the rectangulus, was invented by Richard of Wallingford. This carried out the same task as the torquetum, but was calibrated with linear scales, read by plumb lines. This simplified the spherical trigonometry by resolving the polar measurements directly into their Cartesian components.
|
|
An experimental method for locating the center of mass is to suspend the object from two locations and to drop plumb lines from the suspension points. The intersection of the two lines is the center of mass. The shape of an object might already be mathematically determined, but it may be too complex to use a known formula. In this case, one can subdivide the complex shape into simpler, more elementary shapes, whose centers of mass are easy to find.
|
|
Students of figure drawing will also make use of a plumb line to find the vertical axis through the center of gravity of their subject and lay it down on paper as a point of reference. The device used may be purpose-made plumb lines, or simply makeshift devices made from a piece of string and a weighted object, such as a metal washer. This plumb line is important for lining up anatomical geometries and visualizing the subject's center of balance.
|
|
That Vitruvius must have been well practised in surveying is shown by his descriptions of surveying instruments, especially the water level or , which he compared favourably with the , a device using plumb lines. They were essential in all building operations, but especially in aqueduct construction, where a uniform gradient was important to provision of a regular supply of water without damage to the walls of the channel. He described the , in essence a device for automatically measuring distances along roads, a machine essential for developing accurate itineraries, such as the Peutinger Table.
|
|
That he must have been well practised in surveying is shown by his descriptions of surveying instruments, especially the water level or chorobates, which he compares favourably with the groma, a device using plumb lines. They were essential in all building operations, but especially in aqueduct construction, where a uniform gradient was important to the provision of a regular supply of water without damage to the walls of the channel. He also developed one of the first odometers, consisting of a wheel of known circumference that dropped a pebble into a container on every rotation.
|
|
In these works Getter reconstructs idealistic structures from Western art that emphasize the insufficiency of the human body, using squeegees of paint and mechanical drawing tools such as plumb lines. Her technique in painting tends to put together materials not usually combined. This collagist approach, which uses different and alien elements in the same work, characterized many of the artists in Getter's circle, Michal Na'aman, Yair Garbuz, and Raffi Lavie, who probably was the artist who inculcated this principle in his colleagues and pupils. Getter also studied literature at Tel Aviv University.
|
|
Despite being an important concept for almost 200 years in the history of geodesy and geophysics, it has been defined to high precision only since advances in satellite geodesy in the late 20th century. All points on a geoid surface have the same effective potential (the sum of gravitational potential energy and centrifugal potential energy). The force of gravity acts everywhere perpendicular to the geoid, meaning that plumb lines point perpendicular and water levels parallel to the geoid if only gravity and rotational acceleration were at work. The surface of the geoid is higher than the reference ellipsoid wherever there is a positive gravity anomaly (mass excess) and lower than the reference ellipsoid wherever there is a negative gravity anomaly (mass deficit).
|
|
The reconstructed porta praetoria of Castrum Pfünz, Germany, near the Rhaetian Limes. Late Roman fort in Jordan Late Roman Quadriburgium in Hungary The ideal enforced a linear plan for a camp or fort: a square for camps to contain one legion or smaller unit, a rectangle for two legions, each legion being placed back-to-back with headquarters next to each other. Laying it out was a geometric exercise conducted by experienced officers called metatores, who used graduated measuring rods called decempedae ("10-footers") and gromatici who used a groma, a sighting device consisting of a vertical staff with horizontal cross pieces and vertical plumb-lines. Ideally the process started in the centre of the planned camp at the site of the headquarters tent or building (principia).
|
|
The foundations for quantitative map scaling goes back to ancient China with textual evidence that the idea of map scaling was understood by the second century BC. Ancient Chinese surveyors and cartographers had ample technical resources used to produce maps such as counting rods, carpenter's square's, plumb lines, compasses for drawing circles, and sighting tubes for measuring inclination. Reference frames postulating a nascent coordinate system for identifying locations were hinted by ancient Chinese astronomers that divided the sky into various sectors or lunar lodges. The Chinese cartographer and geographer Pei Xiu of the Three Kingdoms period created a set of large-area maps that were drawn to scale. He produced a set of principles that stressed the importance of consistent scaling, directional measurements, and adjustments in land measurements in the terrain that was being mapped.
|
|
This ceiling represents Lord Burlington's interest in architecture. Alternatively the painted ceiling and its surrounding decoration (including the presence of rats and snakes) can be interpreted as having a Masonic program, as dividers, set-squares, T-Squares and plumb lines were important Masonic symbols of morality. The putto to the left of ‘Architecture’ holds his finger to his lips suggesting silence or secrecy – a gesture mimicking the Egyptian child god of silence, Harpocrates. The idea that this room could have been used for initiation into Masonic mysteries is further supported by the proportions of this room as a perfect cube measuring 15x15x15 feet – the equivalent of 10 cubits by 10 cubits by 10 cubits, the stated dimensions of the Holy of Holies within Moses' Tabernacle according to the Bible.
|
|
Throughout his life, Kenny's work addressed the isolation of the human condition, expressed often through the seated or reclining female figure, abstracted and depersonalised, touching landscape and geometry; often incorporating devices such as plumb-lines evoking a science and accuracy within the emotive shapes. Due to its location, probably Kenny's widest viewed work is his 1992 sculpture – On Strange And Distant Islands – a 25 ft high lateral relief spanning 150 ft of wall above London's busy Limehouse Link tunnel entrance, carved from 70 tons of Kilkenny limestone. His last great series of drawings – The Stations of The Cross – encapsulate the full range of his imagery and references and, according to Professor Brian Falconbridge at a major exhibition of Kenny's work at the Quest Gallery in Bath, rank as one of the finest examples of genuinely religious art within the Christian tradition made since the Reformation. Acquired by the Royal Academy in 1998, the 14 powerful mixed-media drawings represent a modern interpretation of a pilgrimage of the mind, in which the 14 moments of Christ's Passion are captured in time.
|
|