CHAPTER XXXIV.

Condensers with Plates in Oil.

In experimenting with currents of high frequency and higlipotential, Mr. Tesla has found that insulating materials such asglass, mica, and in general those bodies which possess the highestspecific inductive capacity, are inferior as insulators in such de-vices when currents of the kind described are employed comparedwith those possessing high insulating power, together with a smallerspecific inductive capacity; and he has also found that it is very de-sirable to exclude all gaseous matter from the apparatus, or any ac-

Fig. 228.

cess of the same to the electrified surfaces, in order to prevent heat-ing by molecular bombardment and the loss or injury consequentthereon. lie has therefore devised a method to accomplish theseresults and produce highly efficient and reliable condensers, byusing oil as the dielectric 1 . The plan admits of a particular con-

1. Mr. Tesla’s experiments, as the careful reader of his three lectures willperceive, have revealed a very important fact which is taken advantage of inthis invention. Namely, he has shown that in a condenser a considerableamount of energy may be wasted, and the condenser may break down merelybecause gaseous matter is present between the surfaces. A number of experi-ments are described in the lectures, which bring out this fact forcibly and serveas a guide in the operation of high tension apparatus. But besides bearingupon this point, these experiments also throw a light upon investigations of apurely scientific nature and explain now the lack of harmony among the ob-servations of various investigators Mr. Tesla shows that in a fluid such as oilthe losses are very small as compared with those incurred in a gas.