[2] However, Hopkins was unsuccessful as a farmer and, when his first wife died sometime around 1821, he took the opportunity to mitigate his losses and enter St Peter's College (now Peterhouse) at the University of Cambridge, taking his degree of B.A.

Francis Galton praised his teaching style:[3] Hopkins to use a Cantab expression is a regular brick; tells funny stories connected with different problems and is no way Donnish; he rattles us on at a splendid pace and makes mathematics anything but a dry subject by entering thoroughly into its metaphysics.

[2] Hopkins conceived of a largely solid but dynamic Earth threaded with cavities whereby hot vapours or fluids could create locally elevatory pressures.

Such a model was at odds with the ideas of Charles Lyell whose theory was of a "steady state" with a largely liquid terrestrial interior, inside a solid crust no more than 100 miles thick.

Hopkins presented a series of papers at the Royal Society between 1838 and 1842 analysing the Earth's rotation, including its precession and nutation, and using observations to support his theory, contending that they were inconsistent with a fluid interior.

[3] As part of his investigations, Hopkins sought to quantify the effects of enormous pressures on the melting point and thermal conductivity of various substances.

In his second address as president of the Geological Society of London (1853) he criticised Elie de Beaumont's theory of the elevation of mountain-chains and the imperfect evidence on which he saw it as resting.

[2] Ultimately, it was Thomson who tactfully pointed out that, though Hopkins's conclusions about the Earth's structure were correct, his mathematical and physical reasoning was unsound.