100 YEARS AGO

“To those who study the progress of exact science, the common spinning-top is a symbol of the labours and the perplexities of men who had successfully threaded the mazes of the planetary motions. The mathematicians of the last century, searching through nature for problems worthy of their analysis, found in the toy of their youth ample occupation for their highest mathematical powers. No illustration of astronomical precession can be devised more perfect that that presented by a properly balanced top, but yet the motion of rotation has intricacies far exceeding those of the theory of precession. Accordingly we find Euler and D'Alembert devoting their talent and their patience to the establishment of the laws of the rotation of solid bodies. Lagrange has incorporated his own analysis of the problem with his general treatment of mechanics; and since his time Poinsot has brought the subject under the power of a more searching analysis than that of the calculus, in which ideas take the place of symbols, and intelligible propositions supersede equations.” (Maxwell — “Collected Works”, I. p. 248).

From Nature3 August 1899.

50 YEARS AGO

Although much had been written and much had been done, nevertheless neither the Medical Research Council in Great Britain nor the National Research Council in the United States of America was in a position to give any definite answer when, at the beginning of the War, their respective Governments asked for information about the amounts of certain nutrients required by the human body. ⃛ The intention was to give a group of volunteers “a diet virtually devoid of vitamin A and carotene until unmistakable signs of deficiency appeared, and then to determine what dose of vitamin A or carotene was needed to ensure recovery to normal”. ⃛ Perhaps the most unexpected findings in the present instance were the “prolonged delay before the onset of nutritional changes” (eight months of deprivation produced no discernible indication of deficiency). ⃛ Defective night-vision, with a raised rod-threshold and prolonged cone-rod transition-time, and a lowering of the plasma level of vitamin A proved to be the first definite signs of deficiency.

From Nature 6 August 1949.