Porcelain Forestry Insulators

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The first forestry insulator was the "Victor" patented in 1889.  This is patent No. 403,491, which was assigned to the E. S. Greeley & Co.  However, the insulator in the patent does not appear to be intended to be used as a forestry insulator.  Greeley catalogs describe use for suspending telegraph and telephone lines from tree limbs, buildings, or use as a circuit break insulator.   Forestry insulators were used to suspend telegraph or telephone lines to fire lookout towers.  The use of fire lookout towers did originate before the National Forest Service was started in 1905, but doubt that communications with the fire towers was initiated much before the NFS.  From catalogs, it appears that forestry insulators became popular about the time the NFS was organized and especially in the 1910's to 1940's.

Note that most forestry insulators are interlocking.  That is, there is a projection that fits in a matching depression on the other half.  A different interlocking design can be found on OV-S (see ov20).  One of the smaller insulators, r1, does not have an interlocking design.  The mating surface of the two halves is smoothly glazed.  It is not uncommon to find a forestry insulator composed of two halves made by different manufacturers.  And it is not uncommon to find a forestry insulator with one half white and the other half brown.  Many of them are interchangeable.  All were made of dry process porcelain in 7 different basic types or styles.  However, there are at least 5 variations of the round type (see round).

From the 1889 E. S. Greeley & Co. catalog.

From the 1893 E. S. Greeley & Co. catalog.  At right is the only known specimen of the "Victor".  It is embossed on the top side edge above the wire groove: VICTOR and below the wire groove: PAT MAY / 14 89.

The Victor split tree insulator was popular for many years and was still being produced in the 1920's by various companies.  Here are two examples.

Thomas forestry insulator shown in 1901 Western Electric catalog.

Brunt forestry insulator shown in 1909-10 Electric Appliance Co. catalog.

I found several forestry insulators in Arkansas around 1987.

For a list of insulator related COMPANIES, click on the link.

To see images of forestry insulators in catalogs, click on the link.

Below is a list of more than 58 forestry insulators in my collection.  Please report any new ones you have.  The table describes each of the seven basic types.  Click on the Type to see a photo.  Markings and manufacturers are as follows:

BRUNT - G. F. Brunt Porcelain Co.; 1897-c. 1917 (East Liverpool, OH)

C in circle - unattributed

C. P. CO. - Cook Pottery Co.; 1897-1931 (Trenton, NJ)

D & S - Davidson & Stevenson Porcelain Co.; 1913-1920 (Newell, WV)

F - Findlay Electric Porcelain Co.; 1910-1927 (Findlay, OH)

FEDCO - Federal Porcelain Co.; 1917-1927 (Carey, OH)

G - unattributed
G. P. CO. - General Porcelain Co.; 1911-1927 (Carey, OH)

HP - unattributed but probably Akron High Potential Porcelain Co.; 1906-1910 (Akron, OH)

KNOX - Knox Porcelain Co.; 1923-1975 (Knoxville, TN)

MACOMB - Illinois Electric Porcelain Co.; 1910-1953 (Macomb, IL)

PERU - Peru Electric Mfg. Co.; 1892-?? (Peru, IN)

P. P. Inc. - Porcelain Products Inc.; 1927-1956 (Parkersburg, WV)

R. T. & S. Co. - R. Thomas & Sons Co.; 1884-1927 (East Liverpool, OH)

S & S - Smith & Stone, Ltd; 1920-?? (Georgetown, Ontario, Canada)

T or T in a circular impression - R. Thomas & Sons Co.; 1884-1927 (East Liverpool, OH)

THOMAS - R. Thomas & Sons Co.; 1884-1927 (East Liverpool, OH)

Triangle M - Illinois Electric Porcelain Co.; 1910-1953 (Macomb, IL)

VICTOR - unattributed, sold by E. S. Greeley & Co.

Click on link in the first column to see photos of each type of forestry insulator.

or click on this link to see three pages of photos of forestry insulators.

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