The inability of a large number of skilful experimental physicists to obtain any evidence whatever of the existence of the n-rays, and the continued publication of papers announcing new and still more remarkable properties of the rays, prompted me to pay a visit to one of the laboratories in which the apparently peculiar conditions necessary for the manifestation of this most elusive form of radiation appear to exist. I went, I must confess, in a doubting frame of mind, but with the hope that I might be convinced of the reality of the phenomena, the accounts of which have been read with so much scepticism... I am obliged to confess that I left the laboratory with a distinct feeling of depression, not only having failed to see a single experiment of a convincing nature, but with the almost certain conviction that all the changes in the luminosity or distinctness of sparks and phosphorescent screens (which furnish the only evidence of n-rays) are purely imaginary. It seems strange that after a year's work on the subject not a single experiment has been devised which can in any way convince a critical observer that the rays exist at all.

R. W. Wood

From Nature 29 September 1904.


Jean Piaget's reputation as a psychologist in Great Britain is largely based upon a series of books written during 1925–32 dealing with the development of thought, language and moral judgment in the child. But, as he himself points out, this work was merely a prolegomena to his later investigations extending from 1937 to the present day... But though these researches are both theoretically and experimentally an advance upon his earlier work, they have, however, had little effect on English psychological thought... This is probably due to Piaget's introduction of a new and complex terminology, his use of symbolic logic, and the fact that his most important work remains untranslated... The most interesting conclusion which emerges from this important series of experimental researches is that mathematical concepts in their psychological development are ultimately based upon simple logical notions. Indeed, it might be said, without undue exaggeration, that Piaget's psychological studies are the genetic counterpart of Russell and Whitehead's attempt in “Principia Mathematica” to put mathematics on to a logical basis.

From Nature 2 October 1954.