In the Porcelain Insulator News column which appeared in the December, 1988 issue of CJ, we asked for help in identifying the "whatisit" that looked like a mushroom. To refresh your memory, we will show the drawing of this one again. My specimen has a mottled black and tan glaze similar to Ohio Brass or Thomas, with 1-5/8 inch segmented threads. Since the insulator does not have a wire groove, it must have a very special purpose.

Our appeal for help in identifying this oddity did not go unnoticed. Three collectors have offered their help. While some doubts do exist to the exact use of this insulator, we do have a good idea what may have been the intended purpose.

Alan Drew suggested that it may have been used to support an insulator switching platform similar to that shown in a photo from his files (see photo below). He said that it was common practice in the early days to insulate the switchman from grounding potential. Substations would have several of these small switching platforms, many of which were supported by multipart insulators. The wooden platform would have circular recesses cut in the wood which would have allowed it to set firmly on top of four pin type insulators. While this is a possible use for the "mushroom", it would appear difficult to secure the wooden platform to the curved top of the insulator.

Vincent Yeasted sent the photograph shown below of a metal bar with one of these exact mushroom-shaped insulators attached to each end of the curved bar. He said that this metal horn device was attached to the end of a suspension string by a ball socket and the conductor cable was then attached to the metal horn. He suggested that the device may have been used to dampen the line vibrations. While I cannot understand how this device could dampen mechanical vibrations of the conductor since it was attached at the suspension string, it did ring a bell in the back of the ole memory banks.

I searched through all the old manufacturer catalogs in my collection and finally found one photograph from the 1926-27 Ohio Brass catalog. This photo (see top of the next page) probably will not reproduce very well since the catalog photo was on thin paper allowing the images from the other side of the page to show through. A horn device, identical to the one in the photo that Vincent sent with a "mushroom" insulator attached on each end, is clearly seen in the original photo, although probably too small to be seen here. The only catalog reference to this device is the comment at the bottom of the page which stated that the tower in the photograph was installed with "Ohio Brass flux [corona] controls".\

Arcing rings and arcing horns were very prevalent during that time period for use with suspension strings on very high voltage lines. But, the porcelain insulator arrangement on this device seems to me to be quite different in that the ends of the horn are porcelain rather than metal. The all metal arcing horns provided a point of arcing around the insulator string for a surge of current (lightning), thus preventing overloading and damage to the insulators. Then why the use of porcelain insulators on the ends of the horn? The insulator would surely be damaged from the arc. Perhaps this idea did not work very well. Other companies relied on all metal arcing horns and rings of various designs.

Ken Stefan sent what may be another use. He said that he had a magazine or catalog which showed this same mushroom-shaped insulator in use on a small loading coil. But, after much searching, he could only come up with a photograph of a larger coil. The photo at the top of the next page is the one Ken sent from the 1925 Ohio Brass catalog. Ken said that these loading coils were used in radio service. Note the larger, possibly two-piece, insulators attached to the ends of the support rods on top of the coil. The insulators in the photo, as with the "mushroom", do not appear to have a wire groove. Ken believes that the insulators were used to combat the effects of corona since it is obvious from the large vertical insulators at the bottom of the coil that this device operated at very high voltages.

While we have yet to find definite evidence or explanation of the specific use of this "whatisit", it is very likely that it was used in an effort to combat the effects of corona in very high voltage service. Ohio Brass was evidently the manufacturer of this item sometime during the 1920's. The effectiveness in suspension service may have been in question as Ohio Brass catalogs do not mention this device in detail. Hopefully, Ken will find more information on the mushroom that will clear up any doubts we may have.