100 YEARS AGO

A note in the Electrician refers to a curious effect produced by severe thunderstorms upon the glow lamps on the circuits of the Calcutta Electric Supply Co. It appears that immediately following each lightning flash the brightness of the glowing lamps has been observed to increase suddenly, gradually returning to the normal incandescence. This phenomenon has so frequently been observed that the engineers of the company have sought every possible explanation of the curious phenomenon, but have been unable to find any defect in their circuits — which are on the overhead wire system — that might offer an explanation. Indeed, the only conceivable explanation is one which appears so extraordinary that many may find considerable difficulty in accepting it. It is well known that carbon, acting as a coherer in a wireless telegraph apparatus, undergoes the usual sudden decrease in resistance when subjected to electric radiation. It is suggested that the carbon filaments of a glowing lamp may undergo a similar change when exposed to the influence of a tropical thunderstorm in its immediate vicinity. This sudden decrease in the resistance of the filament would, of course, produce a correspondingly rapid increase in its candle-power, after which the gradual self-coherence of the carbon would account for the return of the lamp to its usual incandescence.

From Nature 6 September 1900.

50 YEARS AGO

In his presidential address to the tenth All-India Veterinary Congress held last April in Bombay, Dr. S. Datta, director of the Indian Veterinary Research Institute, Mukteswar, appealed for the creation of an Indian veterinary council, which should be a statutory body set up by Act of Parliament, with power to enforce a high standard of veterinary education in Indian veterinary colleges, to suppress quackery in the veterinary profession and to co-ordinate the work of the various State veterinary departments… He deplored the lack of interest shown by the State and the public in the welfare and improvement of farm stock, and rightly urged that veterinarians should not merely wait until disease occurs and then try to remove or prevent it… Quite apart from political or economic considerations, this reorganisation and development is urgently required for the sake of the farm animals themselves.

From Nature 9 September 1950.