Exploring our archives

I’ve just been referred to this searchable collection of document descriptions and images online, the Waller Collection from Uppsala University. It includes a letter from Hooke to his friend the MP, natural philosopher and antiquary James Long dated 1688 in which he discusses the auctioning of books, sends a new history of China along with some ‘very considerable relations’ of earthquakes in Peru, China, Spain, and India. Hooke puts forward a theory that ‘the Poysenous Exhalations that Issue from such Eruptions may have caused those Distempers in the seasons and constitutions of the air and euen of the helth of People, though in Countrys very Remote, which haue accompanyd them or been always contemporary’. He goes on to speculate that such noxious fumes might have contributed to the ‘Aguish distemper’ then affecting people in England and France, as well as to the plague spreading in Germany. Hooke was of course correct to assume that the effects of earthquakes could have long-term effects on public health through environmental contamination, although inaccurate in linking them to the plague.

Various references to earthquakes also appear in the Hooke folio. At a meeting of 20 June 1677, Hooke outlined his theory that hills and mountains had been originally thrown up by earthquakes. He illustrated this idea by referring to a cliff in his childhood home of the Isle of Wight ‘whose bottom is washt by the sea wherein at a pretty depth below the top and at many fathoms aboue the surface of the sea he found shells of seuerall sorts which he thinks may possibly haue been placed there by earthquakes remouing the superficiall parts of the earth Rasing the bottom of the sea and sinking the surface of the Land.’ He then supported his theory by reading from Varsenius’ account of a huge lake in China that was created after an earthquake. On 12 December the following year, Hooke returned to the subject of earthquakes, this time linking them to volcanoes in explain how metals like gold, which he reasoned were heavy and therefore ought to lie closer to the centre of earth, were occasionally brought closer to the surface. Christopher Wren also came up with various , rather less accurate, theories about what earthquakes could reveal about the earth, reasoning at a meeting of 12 January 1680 that earthquakes might occur when parts of the earth fell down into great subterranean caverns, this fall being the cause of the noise and shaking of the surface of the earth.

The collection also includes manuscripts from several other of the Society’s prominent members, including Joseph Banks, Isaac Newton, Joseph Dalton Hooker, and George Biddel Aidy.

Comments :0

In November 1681, the folio records that ‘Mr. Hooke Produced A new sort of Instrument for Describing the Rhombs or spirall lines vpon the Planisphericall projection on the pole of the world and shewed how the same would easily Describe all manner of Proportionall spiralls whether Greater or Lesse whether wider or narrower. And mentioned also what vse it might be for nauigation and sea charts.’ A few months later, Hooke produced a globe about a foot in diameter fitted with this instrument, and claimed that he could ‘thereby both Geometrically and mechanically Draw all the Rhumb lines vpon it most exactly’. A ‘rhumb line’, although sometimes used to indicate a straight line between two points on a Mercator chart, seems here to have its modern meaning of a curve that crosses each meridian at the same angle and the spirals Hooke refers to describe the way in which a rhumb spirals towards one of the poles.

The instrument designed by Hooke apparently had numerous applications: this is probably what he used in June that year to demonstrate the truth of Archimedes’ ancient theory on spirals, namely that ‘If a straight line drawn in a plane revolves uniformly any number of times about a fixed extremity until it returns to its original position, and if, at the same time as the line revolves, a point moves uniformly along the straight line beginning at the fixed extremity, the point will describe a spiral in the plane.’

Hooke later used the instrument in other ways, attaching it to a compass in order to describe a parabola. This apparently met with some opposition: at a meeting of 15 February 1682, it was noted that Flamstead had ‘cavilled against’ Hooke’s method, ‘affirming it to be fals’. On the repeated demonstration of the working of the instrument, however, the Society agreed that it was ‘true and certain and the best way yet known of describing that curve’. The final reference is in March 1682 and refers to the use of the instrument to describe an ellipse. By this entry Waller has noted ‘Quere Mr Hunt what this was and how performed’. Apparently, then the instrument and its method of use had been lost by the time Waller acquired Hooke’s papers in 1708. Richard Waller, a strong supporter of Hooke’s claims to priority had also made annotations against Hooke’s manuscripts about clocks or watches in Trinity College Cambridge – perhaps believing that they contained the solution to the long-term problem of longitude. He may, therefore, have also believed that this lost instrument was a significant piece of equipment in Hooke’s claim to have invented a new method of planispherical projection to be used in mapping.

Comments :0

A vaguely Valentine’s Day related post today

Observing the transit of Venus, the time at which the planet passes between the sun and earth, is a constant feature of the early records of the Royal Society, who received correspondence from around the world recording the precise times at which it was observed. The purpose of this romantic exercise, similarly to the mapping of the transits of Mercury, was to make observations relating to the position of the sun and planet, using the parallax method. This was pioneered by Edmund Halley, who explains the theory in Philosophical Transactions (translated here for those not keen to read the original in Latin). Mapping transits also has practical applications in navigation as it provides a natural clock with the aid of which longitudes, still a thorny problem in the seventeenth and eighteenth century due to the dearth of reliable timekeepers, could be calculated according to the difference in time between locations on a reference meridian. Perhaps this explains the interest of the East India Company, who allowed Halley to visit St Helena, where he built an observatory, the remains of which can still be observed on the island.

Halley’s work promoted international collaboration between scientists as well as voyages of exploration: most notably Captain Cook’s voyage to Tahiti to observe the 1769 transit. Romantics will have to wait a while to emulate the early stargazers, however, as the next transit is predicted to be visible in 2012.

Comments :0