CONDENSERS WITH PL A TES IN OIL.

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straction of condenser, in which the distance between the platesis adjustable, and of which he takes advantage.

In the accompanying illustrations, Fig. 227 is a section of acondenser constructed in accordance with this principle and hav-ing stationary plates; and Fig. 228 is a similar view of a condenserwith adjustable plates.

Any suitable box or receptacle a may be used to contain theplates or armatures. These latter are designated by b and c andare connected, respectively, to terminals v and e, which pass outthrough the sides of the case. The plates ordinarily are separatedby strips of porous insulating material f, which are used merelyfor the purpose of maintaining them in position. The spacewithin the can is filled with oil g. Such a condenser will provehighly efficient and will not become heated or permanently in-jured.

In many cases it is desirable to vary or adjust the capacity ofa condenser, and this is provided for by securing the plates to ad-justable supports—as, for example, to rods h— passing throughstuffing boxes k in the sides of case a and furnished with nuts l,the ends of the rods being threaded for engagement with thenuts.

It is well known that oils possess insulating properties, and itit has been a common practice to interpose a body of oil betweentwo conductors for purposes of insulation; but Mr. Tesla be-lieves he has discovered peculiar properties in oils which ren-der them very valuable in this particular form of device.