The Steam-Driven Tesla Oscillator

In view of the recent destruction by fire of Mr. Nikola Tesla's laboratory, with all the apparatus therein contained, some of the mechanism most nearly completed and perfected that has gone has been given an additional interest. There is probably no device of Mr. Tesla's of recent date around which more interest has centered than the electrical oscillator, which he first exhibited before a select audience at the World's Fair during the occasion of the Electrical Congress.

Since those instruments were exhibited the mechanism has undergone a considerable change, not in principle but in detail, which has tended to make it more compact, more efficient and in every way better adapted to the peculiar requirements of experimentation in which Mr. Tesla has been engaged as well as to the everyday requirements of the commercial machine. To such an extent had his work been carried in this line that Mr. Tesla was about ready to put the apparatus on the market, and did in fact for some time previous to the fire have his oscillator in practical service in his laboratory.

Through the courtesy of the Century Magazine we are enabled to reproduce here an engraving of the latest type of this machine, made from the last photograph taken of it, which, now that the machine itself has been destroyed, will have additional interest for our readers. This picture was made to accompany an exceedingly well writ ten article by Mr. T. C. Martin which appears in the April number of the Century, to which which our Mr. readers are referred. Martin, as is well known, is Mr. Tesla's historian, and any statements coming from him in regard to Tesla's work are therefore authoritative.

The Tesla oscillator is a steam mechanism, but the "engine" part may be said to have disappeared, so far as that word implies an aggregation of fly wheel, governors, etc. On the one base were mounted two dynamos, or electro-magnetic generating systems, and a small steam chest. There were two pistons, which were vibrated by the steam 80 to 100 times a second. Each of the pistons carried an armature which was plunged reciprocally into the field of the magnets. Normally the engine was run with the two pistons in opposite phase, but they could be set by an independent device in any phase. Above the chest was mounted an independent little oscillator, which in some experiments controlled the steam admission, and made the vibration of the engine quite independent of the load.

This oscillator was operated with steam at 350 pounds pressure, when it needed no packing, as there was no leakage. It was also used at pressures down to the ordinary 80 or 100 pounds. It was used to light up a bank of 50 or more incandescent lamps, some are lamps, and to run various motors, while it also furnished current for a variety of most interesting and novel experiments, all of them suggestive of new departures in the electrical arts, including phosphorescent lighting, the transmission of intelligence long distances without wires, the utilization of the earth's electrical charge, etc.