Through the years there have been subtle changes in the evaluations of the work of Tycho Brahe. As one examines the tracts dealing with novae and comets in which reference is made to the nova of 1572 or the comet of 1577, it becomes quite evident that in different parts of Europe and in the Near East and at different periods of time and among men of different religious convictions different values were placed on his work. The extent of his influence should be distinguished from the measure of his achievements. Moreover, his importance cannot be completely separated from that of Kepler and the horde of other writers who furnished more than a mere background for the display of Tycho's brilliance. Here, as always, there is the danger of assigning to one man innovations that were, so to speak, in the air.

The Geological Society of London was the first learned society to be devoted solely to geology, and its members were responsible for much of the spectacular progress of the science in the nineteenth century. Its distinctive character as a centre of geological discussion and research was established within the first five years from its foundation in 1807. During this period its activities were directed, and its policies largely shaped, by its President, George Bellas Greenough, on whose unpublished papers this account is chiefly based.

The Society began as a small scientific dining club in London, but it developed rapidly into a learned society with a nation-wide membership. It became so independent in outlook and so active in research that it was felt to threaten the esteem of the Royal Society; and little more than a year after its foundation it clashed with the Royal Society (and especially with its President Sir Joseph Banks) so violently that its continued existence was for a time uncertain.

Its development into a large independent society was the outcome of its ‘Baconian’ view of the importance of collecting geological facts as a surer basis for geological theories. For this purpose it initiated an ambitious scheme for co-operative research, which would unite the efforts of ‘philosophers’ with those of ‘practical men’. Only personal reasons seem to have kept the most prominent of the practical men—William Smith—from co-operating with the Society.

Scurvy is now almost a forgotten disease, but it would be difficult to exaggerate its importance in the history of a maritime nation such as our own. To the historian of medical science it is equally interesting, because the various and extraordinary variety of theories concerning it reflect in themselves the intellectual climate of the past. By their repeated refusal to accept the conclusions of an experimental method, by their pedantic reliance on a priori reasoning or antiquated prejudices, the medical authorities of all countries delayed the conquest of this terrible disease long after a cure had been established by men who had practical experience of it. If anyone imagines that even in scientific knowledge progress is inevitable, let him remember that scurvy continued to be the curse of the sea and the hardship of explorers so recent as Scott and Shackleton a hundred years after it had been eliminated in the fleets of Nelson's day.

The rapid growth of seventeenth-century science is said to have been facilitated from four main outside channels: the arts, medicine, economic life and war, each of them influencing, to some extent, the important scientific achievements of the latter half of the century. The bitter campaigns of the English Civil War stimulated a rough and ready empiricism, as military necessity brought forth increasing advances in engineering, navigation, cartography, medicine and surgery. And the impetus to inventive genius provided by long experience in the art of war is well exemplified in the career of the Royalist Commander, Prince Rupert of the Rhine. After nearly forty years of waging war on land and sea, Prince Rupert, German-English nephew of Charles I, spent his retirement in busy experiment; and many of his inventions, though based on his knowledge of weapons, were later adapted for peaceful purposes.

A eudiometer formerly believed to have belonged to Henry Cavendish was probably made after his death. It may have belonged to John Dalton.