Most observers in the 1870s would have been far more impressed by its linearity. In material terms, in terms of knowledge and the capacity to transform nature it seemed so patent that change meant advance that history – at all events modern history – seemed to equal progress. Progress was measured by the ever rising curve of whatever could be measured, or what men chose to measure. Continuous improvement, even of those things which clearly still required it, was guaranteed by historical experience. It seemed hardly credible that little more than three centuries ago intelligent Europeans had regarded the agriculture, military techniques and even the medicine of the ancient Romans as the model for their own, that a bare two centuries ago there could be a serious debate about whether the moderns could ever surpass the achievement of the ancients, and that at the end of the eighteenth century experts could have doubted whether the population of Britain was increasing.