THE MASS MEASURER

See Also: ECCENTRICITY; LEARNED SOCIETIES The Royal Society

Henry Cavendish F.R.S. was a scientist of aristocratic birth¹ who was deeply respected by his contemporaries. His achievements included the identification of hydrogen (1766) and the development of a technique for assessing the density of the Earth (1798).² He carried out work on particular problems at the government's request. Cavendish was disinclined to publish the findings of his personal research. As a result, it only came to be known in the 1870s, when his papers were being edited by James Clerk Maxwell and Edward Thorpe for publication, that he had made the first conscious observations of several scientific phenomena.³

Cavendish was very rich, being termed the wealthiest of the learned and the most learned of the wealthy . Through inheritance he became the Bank of England's largest individual shareholder, yet he wore old clothes and sported a tricorn long after they had passed out of general use. Upon one occasion his bankers informed him that his current account had a vast amount of money in it. They did this in order that he might invest it more profitably elsewhere. He replied that if they found the sum inconvenient, he would arrange for it to be transferred to some other firm that would not feel as discommoded.

At Clapham Cavendish's laboratory and library were in separate buildings from one another. This was because he wished that other scientists should have free access to his books but he did not wish to encounter them. With the exception of his relatives and his fellow Fellows of the Royal Society, Cavendish was asocial. He had an additional staircase constructed in his house on Clapham Common in order that he should avoid accidentally encountering any of his servants.

Cavendish would order food by leaving notes on the hall table and would only enter the dining room once he knew that there was no one else in it. Occasionally, he would entertain a fellow researcher. The meal would usually consist of a leg of mutton and nothing else. Upon one occasion, he was planning to have four visitors to dine and left a note for the customary leg. He was informed that the cook did not believe that the joint would be sufficient to the occasion. He left a second note that read, Two legs of mutton .

Location: 11 Bedford Square, WC1B 3RE. Cavendish s townhouse. (red, grey)

Cavendish Road, Clapham Common, SW12 0DG. Cavendish's rural retreat. The road's northern end was built on what had been the site of Cavendish House. It is the means by which the South Circular joins the south-eastern corner of the Common.

¹. Henry Cavendish's grandfathers were the Duke of Kent and the 2^nd Duke of Devonshire. (The 5^th Duke of Portland was his first cousin three times removed.)

². Cavendish measured the mass of the Earth with a torsion balance that had been designed by his friend the Rev John Michell (1724-1793). The priest had died before being able to use it.

³. Maxwell's decision to edit the papers was an act of thanks to the 7^th Duke of Devonshire, who had provided the funds both for endowing the Cavendish Professorship of Experimental Physics (1871) (the first person to hold the chair was one James Clerk Maxwell) and for setting up the University of Cambridge's Cavendish Laboratory (1874).

David Backhouse 2024