100 YEARS AGO

The rainfall of Madras has often been investigated as regards its relationship to the sun-spot curve, and the first indication of a probable periodicity with sun-spots was pointed out by Sir Norman Lockyer in 1872 and later by Dr. Hunter, in 1877... In a recent number of the United States Monthly Weather Review... Mr. M. B. Subha Rao, of the Madras Observatory, contributes an article on “The Rainfall in the City of Madras and the Frequency of Sun-spots.”... Dealing with the variation of the rainfall and the sun-spot curve from the year 1811, he is led to deduce that the minimum rain “occurs almost exactly on the year of minimum frequency of sun-spots, the difference being only a year in a few cases.” He finds, further, that the “maximum rainfall also takes place when we have the maximum frequency of sun-spots,” but he guardedly adds that the difference amounts sometimes to two or three years.

From Nature 5 February 1903.

50 YEARS AGO

Mr. H. Lloyd, of the Yorkshire Electricity Board, writes: “66,000 volts transmission lines in the Yorkshire and North Lincolnshire areas had been subject to a number of mysterious faults, which nearly always occurred about dawn, for several years before the trouble was found to be caused by kestrels which were escaping alive. The points of interest in pursuing the investigation were, first, how was it that the birds were surviving 38,000 volts applied across their bodies, and second, what was attracting them to the lines? The incidents always occurred in the early morning or in the misty weather when the birds' plumage could be assumed to be damp. The flashover is initiated across the damp wings when the bird is banking steeply with its back to the insulators, and current does not pass through the bird's body. The speed at which the bird is travelling takes it out of the path of the arc before it becomes too severely burnt... One day, a substation attendant, during misty weather, noticed a kestrel circling a string of insulators in ever-narrowing circles... The insulators, as is usual under humid conditions, were discharging and emitting an intermittent buzzing noise, and this seems to provide the attraction... This seems to imply that kestrels hunt by ear as well as sight.”

From Nature 7 February 1953.