During the mid-nineteenth century, there were two distinct religious mentalities among British academics. The North British school was religiously conservative and commercially engaged thanks to the influence of Presbyterianism and Calvinism. Northern English and Scottish researchers played a key role in the development of thermodynamics, which was motivated by the desire to design ever more efficient engines. By contrast, in the South, mentalities of Anglicanism, agnosticism, and even atheism were more common. Academics such as the biologist Thomas Huxley promoted "scientific naturalism."