100 YEARS AGO

Photography for Naturalists. The advantages of photography as compared with wood-engraving for the illustration of works on natural history are in many ways so great that any attempt to perfect and popularise the methods in use should be heartily welcomed. Quite apart from artistic effect, the great superiority of photography is that it ensures absolute accuracy, and, when living animals are the subjects, shows them in natural attitudes. In wood-engraving there are several sources of error which only too frequently make themselves apparent. In the first place, the draughtsman may make a blunder. But too often it is the engraver who is in fault, very frequently from mistaking the nature of some feature in the drawing he has to reproduce. For example, the author of the volume before us calls attention to a curious engraver's error in a well-known popular work, where, from some misconception, the mouth of a stickleback appears in a totally wrong position.

From Nature 14 November 1901.

50 YEARS AGO

The progress of nuclear physics in the past two decades has depended greatly on the use of machines for producing high-energy particles; these fast particles are used for bombarding atomic nuclei with the aim of producing nuclear transformations. Though the first machines were built nearly twenty years ago, much still remains to be known about the atom. It must be remembered that we know today about nine hundred different kinds of atomic nuclei; only three hundred of them are found in Nature, while the remainder have to be prepared artificially, using either high-energy particles or neutrons coming from a nuclear pile. Furthermore, each of these nuclei is a complicated structure, with features many of which are still not understood. Finally, quite new phenomena have been recently discovered, such as the artificial creation of mesons in high-energy nuclear collisions. These mesons, previously found only in the cosmic radiation, can now be studied much more closely, and their study is thought to bear closely on the riddle of the 'nuclear forces', the forces whereby the particles in an atomic nucleus are held together... there are at least three kinds of mesons with different mass, each of them unstable and prone to transform itself within a small fraction of a second into two photons.

From Nature 17 November 1951.