Stanley Jevons trained as a chemist at University College London in the early 1850s. He is known as one of the founders of the marginalist theory of consumer behaviour which has become part of the standard equipment of modern economics. Before turning to political economy in the 1860s, he worked for about five years as one of two gold assayers in Sydney for the newly created mint. He was recommended for the job by his cousin William Roscoe, himself a noted chemist.
These two pages are taken from the last pages of Jevons' diary for 1858 and mark a dramatic moment in his life. Approaching the end of 1858, Jevons assesses his fortune and makes predictions for the future. He uses the space reserved for November but dates his entry to 3 December. He reports on his wealth at the end of 1858, how it had changed from the previous year, and then begins to reason about how long he could live off his wealth, opening up the possibility of returning to London to study political economy at University College. He speculates on other sources of income - including his share of his inheritance, his father having died while in Australia. Returning to London to study political economy is an important and uncertain step, although Jevons had always planned to stay in Sydney for only a limited period. Now, however, he has just received an offer to become head of currency analysis at the newly established mint in Melbourne, which would increase his annual income from around £800 to £2,000 a year. This is not an offer he can simply put aside, as he has financial commitments to his brothers and sisters. Nevertheless, it is clear that accepting this offer would prevent him from pursuing his studies in political economy, which are increasingly the focus of his attention. Thus, recording the balance of his assets is an important step in assessing future options. It allowed him to put this complex, life-changing decision into perspective.