Tesla's Original Work

[From the London Electrical Review.]

In a letter to the ELECTRICAL REVIEW, New York, Tesla describes the results of some recent experiments he has made in vacuum tube lamps, and in their application to photography and other purposes. Along with the letter are published copies of photographs taken with Tesla's new vacuum. One is a portrait taken by the light of a single vacuum lamp at a distance of five feet with an exposure of five seconds. Another is a page of letter-press taken by a single vacuum tube at a distance of four feet with an exposure of two seconds. The photographs are not equal to sunlight photographs, but resemble more those taken with a single magnesium flashlight, the shadows being very harsh, but the amount of detail is considerable. * * * The great superiority in efficiency of his system over earner attempts at vacuum tube lighting he considers is principally due to the use of his improved apparatus for "producing economically harmonical electrical vibrations of extreme rapidity," referring, no doubt, to his oscillator recently described in the Electrical Review. Tesla promises soon to give further details of his system. The well known originality of nearly all Tesla's investigations leads us to look forward to the publication of the full description of his new system.