The JHI winter lecture was given by Professor Allan Chapman of Wadham College, Oxford University, on Tuesday 8th December 2015, in Darwin Lecture Theatre, to an audience of almost 200 people. He took as his theme the north-country astronomers, Horrocks, Crabtree and Gascoyne. He explained to the audience how the ideas of Copernicus and Kepler and the other famous European astronomers of the day would have been well known to Horrocks and his contemporaries, as scientific knowledge flowed freely across Europe in the 17th Century, and Horrocks would have learned of these ideas during his time at Cambridge University.
Kepler predicted the Venus transit of 1631, but it was Horrocks who first predicted that Venus transits should occur in pairs, roughly eight years apart, and predicted the subsequent transit of 1639. Furthermore, Horrocks predicted the date of the 1639 transit, on November24th, and urged his friend Crabtree to try to observe it. Both men successfully observed the transit, although in Horrocks’ case, it was only after he had completed his duties in the Sunday service at Much Hoole Parish Church. From the observations they were able to calculate the orbital period of Venus, as well as its size.
Jeremiah Horrocks dies on January 4th 1641, but history does not record how he died. This lecture took place only a few weeks before the 350th anniversary of Horrocks’ death. Professor Chapman speculated that perhaps he fell from his horse during his journey to see Crabtree. Horrocks’ work was published posthumously and much admired by later scientists, including Sir Isaac Newton. The audience was entranced by Professor Chapman’s account of this tale of scientific discovery.
Much Hoole Parish Church near Preston, Lancashire, where Horrocks assisted with the Sunday service on the day of the 1639 Venus transit.
James Crabtree observing the 1639 transit of Venus. Painting by Ford Madox Brown in Manchester Town Hall.
Professor Allan Chapman with JHI Director Professor Derek Ward-Thompson.
Stained glass window in Much Hoole Parish Church, near Preston, Lancashire, commemmorating Horrocks observing the 1639 Venus transit.
Carr House, Much Hoole, near Preston, Lancashire, where Horrocks lived, and from where he observed the 1639 Venus transit (reputedly from the first floor window just right of centre).
Jeremiah Horrocks observing the 1639 transit of Venus. Painting by Eyre Crowe.
Professor Allan Chapman and the statue of Jeremiah Horocks. Sulpted by Phillp Garrett
Professor Allan Chapman and the statue of Jeremiah Horocks. Sulpted by Phillp Garrett