There is no evidence to suggest that even as late as January 1672, when Newton was elected a Fellow of the Royal Society, anyone (except those unknown few who had in the previous years attended his Lucasian lectures at Cambridge) had any inkling of his new theory of colours. His name exploded on the scientific scene as the inventor and constructor of a new kind of telescope—what later became known as the reflector (which was somewhat misleading compared with its name during the seventeenth century: the catadioptrical telescope). Had the erudition of the London virtuosi been a little broader, they would have known that in fact he was not the inventor of the telescope, even though the precise form he gave it was his. Not only was the idea a hundred years old, during which period it was repeatedly suggested by various writers, but also Newton himself took the idea straight from the most recent of these suggestions, namely that included in James Gregory's Optica promota of 1663. The situation becomes even more ironic when we realize that the new instrument was admired for wrong reasons and on merits that were far from Newton's intentions. Nevertheless, admired it was, and there was a good reason for this: Newton's instrument was in fact the first reflector actually to be constructed and, moreover, for a few weeks (before its mirror became tarnished) it performed quite well. Several astonomers became interested because of the high magnifying power relative to its dimensions (about 7 inches long, with a magnification of 38).

The graphical presentation of experimental data in the physical sciences has several advantages which today are too familiar to require very detailed enumeration. Its greatest strength lies in the clarity and succinctness with which it displays the information contained in tabulated results: for the experimenter a graph provides a rough and immediate check on the accuracy and suitability of the methods he is using, and for the reader of a scientific report it may convey in a few seconds information that could only be gleaned from a table of measurements by hours of close study. There are occasions where only the analysis of experimental graphs will provide the information we require, but usually the actual analysis of results is carried out nowadays by computational methods. The use of graphs is therefore not so much a necessary part of scientific procedure as an extremely useful one, and one that is often taken very much for granted.

There are several differences between the theories of matter published by René Descartes in 1637 and 1644 which deserve attention. The differences follow from Descartes's well-known identification of substance with spatial extension, and his consequent rejection of the void. Since there was no void space, Descartes argued, a very finely divided subtle matter must extend throughout the universe in order to fill all space not otherwise occupied by the less finely divided ordinary matter. In the 1637 treatises La dioptrique and Les météores Descartes described only one kind of subtle matter, the primary function of which was to transmit the action of light. Yet when he came to write Principia philosophiae (1644), he believed that the subtle matter was divided into two separate elements. One of these remained an aether for light transmission, but the other had lost this property and was believed instead to be active in magnetic effects and in the electrification of glass, and to form part of the substance of flame.

The role of Robert Chambers's anonymous Vestiges of the natural history of creation in popularizing evolutionary ideas establishes it as a significant work in the history of science even though its intrinsic scientific value is not great. Its fascinating subject, a universally applicable developmental hypothesis, piqued the curiosity of the nineteenth-century reading public. The clientele to whom the book especially appealed was not too concerned with errors in fact and unsupported generalizations, but instead was attracted by the smoothness of its literary style and the glibness of its pronouncements. These same characteristics caused it to be an anathema to both scientists and clergymen, who joined together to voice their disapproval; they agreed that the ideas in it were potentially harmful to those untrained in scientific procedures and unaware of the book's inherent religious heresies.

In Italy the physical sciences had several decades of prosperity during the first half of the seventeenth century, largely because of the genius of Galileo Galilei and the efforts of a small constellation of his talented followers. But Galileo died in 1642, and before the end of the 1640s three of the most gifted of his disciples, Castelli, Renieri, and Torricelli, had also gone to a better life, to use the favourite euphemism of the time. Thereafter Tommaso Cornelio at Naples, Giovanni Alfonso Borelli at Messina and later at Pisa, as well as some lesser men, carried on the new science, and in 1657 the scientific enthusiasm of the Grand Duke Ferdinand II of Tuscany and his talented brother Leopold led to the short-lived Accademia del Cimento (1657–67), whose clear-cut and totally empirical programme of experimentation, reported on in 1667 but carried out mainly before 1662, was the last Tuscan flame to rise from the Galilean embers. Physiology and anatomy continued to develop, and north of the Apennines there was activity in astronomy and in optics, but the last was an isolated spark in the general gloom.

In a recent paper on the origin of G. N. Lewis's concept of the shared electron pair bond, I argued that the sources of Lewis's novel conception were certain ideas of J. J. Thomson and Alfred Parson. Yet the only influence that Lewis explicitly acknowledged was neither of these, but Alfred Werner's. The following statement appears in his book, Valence (1923):

I still have poignant remembrance of the distress which I and many others suffered some thirty years ago in a class in elementary chemistry, where we were obliged to memorize structural formulae of a great number of inorganic compounds. Even such substances as the ferricyanides and ferryocyanides were forced into the system, and bonds were drawn between the several atoms to comply with certain artificial rules, regardless of all chemical evidence. Such formulae are now believed to be almost, if not entirely devoid of scientific significance. Such abuse of the structural formula inevitably led to a reaction which found its best expression in the publications of Werner. His Neuere Anschauungen … (1905) marked a new epoch in chemistry; and in attempting to clarify the fundamental ideas of valence, there is no work to which I feel so much personal indebtedness as to this of Werner's.

In recent years John Herapath has emerged as an important figure in the early history of the dynamical theory of gases. In a series of papers published in 1821 and 1822 he outlined an elaborate theory of the states of matter, specific and latent heats, vapours and gases, culminating in a theory of the gravitational ether. This work was based on the rejection of the caloric theory of heat and was founded instead on the idea that the particles of matter were in constant motion; the forces of caloric were replaced by the transfer of momentum. Herapath's is one of the earliest of dynamical theories of gases to be worked out in any mathematical detail.