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Star Tracks by Frank Swies

Discussing star-embossed glass insulators is similar to discussing the Loch Ness monster. Everyone has a theory or a belief but records are virtually non-existent. Why they were made, when, where and by who remains open to investigation. Following is some of the accepted information.

What Are We Looking For ? . . . . .

The number of styles that are star-embossed is known from actual sightings. The styles are identified by Consolidated Design (CD) number  designed by N. R. Woodward (1). They are:

102,    104,    106,    112,    113,    133,    134,    145,      160
161,    162,    162.1  162.3  164,    185,    200,    260

What Did The Stars Mean ?. . . . .

Embossing on glass insulators serves two principle purposes; the first is to identify the manufacturer (Brookfield, Hemingray,etc.), the second is to identify the customer (user) for which the insulator was made (T-H. E. CO., CITY FIRE ALARM, POSTAL TELEGRAPH CO., A.T. & T.). Which purpose did the star embossing serve?
The Mansfield-Nowlton Glass Works of Lockport, New York, made bottles, fruit jars and other utility glass items with a five-pointed star logo.  There is known to have been a star logo used by the Newark Star Glass Works of Ohio.  The Acme Glass Company made use of a five-pointed star mark. There was also a Star Glass Company in New Albany, Indiana (1860 to 1900).  There is no evidence to show that these star logo companies ever manufactured glass insulators.

A Little History

In 1888-89, the Sprague Electric Railway and Motor Company of New York contracted to connect a hydroelectric generating station to fourteen Sprague motors along an eighteen-mile circuit. The intent was to provide power to the rapidly growing gold mining industry as well as the electric street railways. Quality problems required the extensive rewiring of the of the Sprague motors. Internal problems and financial shortfalls threatened the economic survival of the company (2).

During this same time period several of the Edison-owned companies merged into a single entity known as the Edison General Electric Company intending to provide municipal electric lighting. Expansion of physical properties was required. Sprague was absorbed by Edison General Electric and a new company, the General Electric Company (G.E.) was formed.

The Thomson-Houston Company was engaged by G.E. to provide the necessary transmission equipment.  Research by Joe Maurath, jr (3) discloses that the Thomson-Houston Company never produced glass insulators.  Brookfield and Hemingray were contracted to produce the desired glass insulators.  Why is this important?  A 1904 General Electric Company catalogue reveals that star-embossed insulators were part of their product offerings. The insulators were shown as:

   Cat. No. 9322    Pony Glass Insulator
   Cat. No. 9310    Deep Groove, double petticoat insulator
   Cat. No. 9311    Extra Deep Groove, double petticoat insulator
   Cat. No. 9312 Pony, Deep Groove, double petticoat insulator   
These items are embossed with a five-pointed star.  Today we refer to these insulators as CD 112, CD161, CD 162 and CD 160 respectively.  N. R. Woodward relates that General Electric had insulators made for them embossed with a raised, five-pointed star. It seems safe to assume that the five-pointed star embossing was intended as a user mark for General Electric items.

Who Made 'Em? .  .  . Where? .  .  . When? .  .  .

The major makers of Star insulators are believed to be Brookfield, Sterling, Novelty, and Harloe.

William L. Brookfield stated that he believed that insulators, embossed with five-pointed stars, were made at the Brookfield Glass Company plant at Old Bridge, New Jersey (4).  This seems possible since G. E. came into existence in 1903 and the plant at Old Bridge was already producing insulators for the Thomson-Houston Electric Company (T-H E. CO.). These molds were retooled to G. E. CO. and possibly a Star after Thomson-Houston became part of G. E.

In 1902, the old Elmer Glass Works of Elmer, New Jersey, leased space to the Sterling Glass Company. The following year, the company was sold to the Harloe Insulator Company of Hawley, Pennsylvania.  This facility, known as the "Lower Works", produced glass insulators when fuel was available.  The insulators produced were of the CD 102, CD 112, CD 160, and CD 164 variety.  Things did not go too well and in October, 1903, the Harloe Company vacated the plant and moved production to their Hawley, Pennsylvania facility.

In 1903, the Gilchrist Jar Company, located in Elmer, was sold to the Novelty Glass Manufacturing Company. This plant, known as the "Upper Works", began producing insulators as a main product. The Brookfield Company forced the closing of this plant in 1907 due to a patent infringement suit.

Ray Klingensmith excavated the Elmer sites and found remnants of Star insulators.  It seems evident that Sterling, Harloe, and Novelty made insulators for G. E. at these Elmer works.

Prior to 1912, insulator needs for the area West of the Rocky Mountains had been satisfied by Brookfield and Hemingray (5). Hemingray was already producing CD 134 insulators for the T-H E. Company when it became part of G.E.  Retooling of the molds to produce an embossed star quite possibly occurred at that time.

Color Clues .  .  .  .  .      

Color and Quality are invaluable aids in determining origins of Star insulators.  Colors ranged from light blues to dark greens with variations now and then. The colors are determined mainly, by the sand source but the use of cullet and additives sometimes alters resulting colors.  The main drawback to identifying by color lies in the fact that color determination is so subjective. (How many collectors are confident in telling the difference between teal green and dark green aqua?) Differences in light source and possible color impairment of the viewer further complicate identification.

When the Brookfield plant was located at Old Bridge the colors produced were different that the colors resulting from the Bushwick plant in Brooklyn. The Old Bridge plant used a good deal of cullet with their New Jersey sand and a pronounced green color resulted ( i.e. dark aqua, dark green, and olive green).

Novelty Glass Company operated the "upper" works at Elmer.  New Jersey sand was used and the resulting glass was mostly green.

Sterling operated at the old Elmer "lower" works. One noticeable quality of their glass was the purity of color. Clear, light blue aqua color glass was produced.

Harloe had a plant in Hawley, Pennsylvania that produced glass insulators from 1902 through 1907.( Do not confuse Harloe with the Hawley Glass Company of 1872 - 1885). The sand quality and the use of cullet produced a crude aqua to blue aqua glass that is sometimes referred to as snowy or milky.

Prior to 1889, Hemingray operated a plant in Covington, Kentucky.  The glass produced ranged from blue to green in unpredictable variations.  1890 - 1930 saw the construction and continuous operation of a second plant in Muncie, Indiana. A more uniform blue-green color glass was produced. Color alone cannot be relied upon for identification.  An 1896 Hemingray letterhead proclaimed "Flint, Green, Amber and Opal Glass Manufacturers."

Tidbits And Pieces .  .  .  .  . 

One of the oddities of star insulators that is mentioned from time to time is the wedge-shaped drip point. It appears that two adjacent drip points are joined and form a wedge (Figure 1). There are two styles of star insulators that exhibit this feature: the CD 102 pony and the CD 162.3 signal. The purpose of this design is unknown, as is the manufacturer. Both exhibit swirl start threading which is considered by many as a Brookfield characteristic.
Figure 1
Figure 1 Wedge drip points

Another oddity that is sometimes seen is the "Elmer Ring".  This circular mark is found at the top of the pin hole.  This feature seems to be unique to pieces made in Elmer, New Jersey and is thought to be a Novelty Glass characteristic.

All star-embossed insulators were made in three-piece molds (no MLOD).  An exception is found in the case of the star mine insulator which  came from a two-piece mold.  There have been no clear glass star insulators found as yet.  An attempt to correlate star attitudes, size and colors with manufacturers proved inconclusive.

Meet The Family .  .  .  .  .

Presently, there are 17 styles of star-embossed glass insulators that have been identified.  When the variations of embossing are considered the number jumps to 38.  Add to this the possibility of multiple manufacturers, numerous mold styles and color variations ant the future of the prospective star collector becomes challenging. The following is a brief introduction to members of "The Family".

CD  102

The star pony "herd" is possibly the largest group of star insulators.  McDougald's vol. 2 lists the known CD 102 embossing as follows:

Index          Description
010    Dome number, star on front skirt, smooth base
020    Dome number, star on front skirt, sharp drip points
030    Dome number, star on front skirt superimposed over a  blotted out S. F. , smooth base
040    Dome number, star on front skirt superimposed over a blotted out S. F.,  sharp drip points
050    Star on front skirt, smooth base
060    Star on front skirt, sharp drip points smooth base
070    Star on front skirt, small vertical bar on rear skirt smooth skirt
080    Star on front skirt, star on rear skirt, smooth base
090    Star on front skirt, wedge-shaped drip points    
100    Star on front skirt, VERY small star on rear skirt, smooth  base
110    Star on front skirt superimposed over a partly blotted out S. F. ,smooth base
120    Star on front skirt superimposed over a partly blotted out S. F., sharp drip points

One noted collector (Brent Berger) has developed a method of classifying star ponies by mold sets, he believes that the Embossing Index system does not reflect the subtle nuances of the various mold variations. He uses the following descriptive terms:

Tall Skirts - This mold set is very common with many sub-variants. At first glance, most of the skirts seem alike, however, dome profiles vary from short, sharp edged to tall and rounder.
Figure 2
Figure 2 Tall Skirt

Fat Heads - Characterized by slightly larger domes. Skinny Skirt and Stout Skirt variants exist. The skinny skirt tends to be slightly taller than the stout skirt version. Concave sides are found on some of the skinny skirt versions.
Figure 3
Figure 3 Fat Head, skinny skirt (left), stout skirt (right)

Shrunken Heads - This set constitutes a unique union of stout fat head skirt with the dome of another, undersized set.
Figure 4
Figure 4 Shrunken Head

Shotgun Skirts - These very common, smaller insulators have star embossing on the front and rear skirt. The sides are almost parallel lending to a "gun barrel" appearance
Figure 5
Figure 5 Shotgun Skirts

S.F. Style - These are created from reworked S.F. insulators. The second period is visible. These are found with smooth bases or sharp drip points.
Figure 6
Figure 6 S.F. Style

Blobtop - Taller, oversized, round dome styles embossed front and rear with a star. There exists a less round dome version with a sharper upper wire ridge.
Figure 7
Figure 7 Blob Top

There are several features of star ponies that seem unique and bear relating. Some of the CD 102 star ponies (010, 020, 030, and 040) are numbered on the dome. Numbers 1 through 3 are common. Dome numbering (mold numbers) is not unique to star insulators however, since it was a common practice of Brookfield to use dome numbers and letters and Hemingray made use of dome letters. The facts that several star ponies carry dome numbers and are found mostly in darker green colors prompts the belief that Brookfield was involved in the production of these star ponies.

Several star CD 102 ponies have sharp drip points. In the early years drip points were considered a unique Hemingray feature. There is, however, a strong belief that the sharp drip point star insulators were produced by Brookfield. This belief has not been substantiated.

Some descriptions refer to a star superimposed over a blotted out S.F. It appears that in the retooling of S.F. molds the second period was overlooked and remains in the lower right part of the star. Whoever made the S.F. insulators evidently was involved in the production of some star insulators (Figure 8).
Figure 8
Figure 8 S.F. Blot Out

Another unusual mark found on some star insulators is the "vertical bar."  The bar is much smaller than is usually found (Figure 9) being 3/16 inch. It appears more like seepage from the edge of an elliptical blot out. What was blotted out is open to conjecture but it may have been a "B" or another star. Several of these embossings have appeared so it is not a one-time anomaly.
Figure 9
Figure 9 Verticle Bar

Some interesting insight can be gained by comparisons. Compare the CD 102 ponies of the following:

Star [040] (S.F.Style)……………....….S.F. [020]
Star [080] (Shotgun)………………..….Hawley [050]
Star [050] (Fat Head, Skinny Skirt)……Sterling [020]
Star [050] (Fat Head, Skinny Skirt)……Brookfield [020]
Figure 10
Figure 10 Comparison from left, S.F., Shotgun, Fat Head skinny skirt, Fat Head stout skirt

CD  104

This insulator was designed for subscriber and open wire telephone use. N. R. Woodward and M. Milholand refer to this style as a "Pony," Tibbits called it a "Beehive" (6) and Brookfield called it a "National Pony." The known manufacturers of this style (Brookfield, National Insulator Company and Standard Glass) retained a great degree of similarity. 
Figure 11
Figure 11 CD 104

Only one embossing style [010], which features a single star on the front skirt, has been recorded.  There are, however, variations in the size of the star indicating that a variety of molds were used. Colors are mainly light blue and light aqua with occasional green and green aqua being found.
A "Wide base variant" is sometimes heard of.  The only wide base variant CD 104 that has been recorded is that of the New England Tel & Tel CD 104 (7). There are no records showing that the CD 104 was made at Elmer even though an "Elmer Ring" is sometimes seen.

CD 106

CD 106, nicknamed Pony, was designed to serve primarily rural systems. The style was widely copied and produced by the major insulator companies. Curiously absent from the wide production is the Brookfield product.  None have been observed. Dimensions are relatively consistent with the sketch in figure 12. The CD 106 Star has been widely used and has been found in virtually every quarter of the country.
Figure 12
Figure 12 CD 106

A sampling of fourteen CD 106 Stars all had a single star. In each case, the star measured ½ inch and consistently pointed downward. All Star CD 106 had smooth bases while some other manufacturers had sharp drip points.

CD 112

The CD 112 double groove insulator, (nicknamed Double Groove Pony) was designed for residence drop line / exchange line interface. This style insulator was developed and produced for nearly 20 years by Brookfield. Star embossed fragments of this style have been unearthed at the lower works site of the Sterling Glass Works (after acquisition by Harloe in 1903). Colors are generally aqua with occasional green shading from light green to dark olive

Current literature lists two embossing indices for the CD 112 Star; [010] single star and [020] two star. Actually, five mold variations have been found. These are shown in figure 13 as follows:

[010]    Flat Side, Sharp Corner, one star
[010]    Flat Side Tall, Sharp Corner, one star
[010]    Flat Side, Rounded Corner, one star
[010]    Barrel, Rounded Center, one star
[020]    Flat Side Tall, Sharp Corner, two stars
Figure 13
Figure 13 CD 112 mold variations

The [010] Flat Side Tall is considered a rarity. Physically, the dimensions are identical to the [020] Flat Side Tall. It could be helpful to remember that "rounded edge" molds are a familiar Brookfield trait. Sharper edges are found on Hemingray molds.

CD 113

At least four glass companies are known to have produced the CD113 double groove pony. This insulator, designed to serve rural exchange telephone lines, was manufactured by Armstrong, Hemingray, Westinghouse, Whitall Tatum, and possibly others. Exactly who it was that produced the stars is unknown.

Colors commonly found range from light blue through aqua to an olive green.

The most often found CD 113 seems to be the Hemingray #12.  It is a temptation to attribute Star 113 production to Hemingray. This may be true, however, Hemingray used drip points very extensively and the Star unit is smooth based. In addition, the Hemingray has a different pin hole with an extra thickness of glass to reinforce the lower wire groove since the threading starts above the wire groove.  The Star 113 threading extends below the wire groove and provided sufficient thickness to support a lower wire groove (Figure 14).
Figure 14
Figure 14 CD 113  Star left, Hemingray right, CD 106

A theory sometimes emerges that the CD 113 Star was made from reworked CD 106 Star molds. From outward appearance it would seem possible but in practical terms it is unlikely. The bottom of the pin hole/inside skirt of the two insulators are markedly different (Figure 14). The skirt wall of the CD 106 seems too thin to safely support an added wire grove.

CD 133

This smaller version Star signal (Figure 15) was intended for use with open wire telegraph, telephone lines and other, low voltage applications. The lack of an inner skirt prohibited use with high voltage circuits due to the short distance from line to ground (mounting pin).
Figure 15
Figure 15 CD 133

The CD 133 Star is sometimes called the "bullet" due to the narrow dome. The colors range from light blue through aqua to various shades of dark green suggesting Novelty Glass or early Brookfield origins. Most of the CD 133 Star signals have an "Elmer Ring". There is an existing belief that the CD 133 evolved from early CD 726 - 728.8 thus accounting for the smaller size.

CD 134

The CD 134 insulator, known as a deep groove signal, was used to carry Thomson-Houston circuits in the late 1890s (Figure 16). The Hemingray made insulators carried the T-H E. Co. embossing and are found in aqua to light green colors. Brookfield is believed to have produced the CD 134 for Thomson-Houston. When the change to General Electric came, the molds were reworked to read G. E. Co. Production continued until the plant closed in 1922. These Brookfield pieces are found in dark green, dark aqua, and olive green.
Figure 16
Figure 16 CD 134

The CD 134 Star has characteristics of both Brookfield and Hemingray.  The two pieces are similar in dimension  and can be identified only by color and quality. There is no "Elmer Ring" in the Star unit. No inner skirt is present.

CD 145

The CD 145 "Beehive" was intended to replace the much older "Compromise" insulator. Samuel Oakman's  1884 patent #14674 was adopted for open-wire telegraph use. Several supply houses manufactured this design. McDougald's price guide mentions three commonly seen embossing index numbers:

[010]    "Standard", single star, smooth base
[020]    "Pointed Dome", single star, smooth base
[030]    "Postal"  or "Tall Dome" style, single star, smooth base
Figure 17
Figure 17 CD 145

There have been five versions of the CD 145 Star seen. The [010] index has been followed by two variations still considered as [010], (Figure 17).  All of the five versions have smooth bases and short inner skirts that do not extend to the outer skirt.

Colors range from light blues through aqua to variations of dark green. Identification of the manufacturer has been complicated due to the color variations and dimensional differences. These variations suggest that the CD 145 Star was made with several molds.  The Standard, Pointed Dome and Tall Dome styles are believed to be products of Sterling, Novelty and/or Harloe glass companies. The variants suggest that Brookfield and Hemingray were involved in the production of some CD 145 Stars using modified mold embossings of their own CD 145s. The Brookfield connection with Novelty Glass is questionable because, at that time, Brookfield was suing Novelty over a patent infringement (8).   Distribution of the Star CD 145 seems diverse; examples have been found in Ontario, Canada as well as various parts of the U.S.

CD 160

The CD 160 Star insulator (Figure 18) was originally intended for rural telephone system use. It is a smaller signal type with a smooth base, a single star and an inner skirt which does not extend down as far as the base. It should not be confused with a CD 133 which does not have an inner skirt.  The color distribution ranges from light aqua through yellow green to light aqua. The size and attitude of the star embossing together with the glass colors leads to interesting speculations.  Small stars (3/8 in.), pointing downward are found on the darker insulators and have wider wire ridges suggesting Brookfield. There is no "Elmer Ring" found.
Figure 18
Figure 18 CD 160

A slightly larger star (7/16 in.) pointing upward is found in aqua or light aqua insulators showing an "Elmer ring."  These insulators have a more conventional tapered wire groove suggesting Harloe (lower works) origin prior to the move to Pennsylvania.  A third type of star is found on the light blue and light green insulators which contain impurities and bubbles. The star is large (1/2 in.), pointing upward. The clear colors suggest Novelty glass. An "Elmer Ring" is present.

CD 161

An early (ca.1904) General Electric supplies catalogue  includes a picture of a "Deep Groove, glass, petticoat" insulator.  A cut-away picture reveals an inner skirt that does not reach to the base level.  N. R. Woodward shows only three companies involved with the CD 161; California Glass, Brookfield, and Star (9).  California Glass tended towards a complex darker color while Brookfield glass has a characteristic darker green color. This color difference supports the belief that the Brookfield company produced the CD 161 Stars. Most of the Star 161s are a green to darker green color.  In addition, the California Glass Insulator Company was less likely to have had a connection with Star Manufacture because of its late start-up date (ca. 1912). Harloe is believed to have made Star CD 161 units after taking over the Sterling operation.  The CD 161 Star is found with both a smooth base and sharp drip points (Figure 19). Embossing includes a single star. Colors range from aqua through green to dark green. Embossing is consistent ( 7/16 inch star, pointed downward).
Figure 19
Figure 19 CD 161
Occasionally, the Star CD 161 and 162 are confused. Close examination discloses that the CD 161 Star crown is relatively flat and wide ("broad shouldered") and the skirt almost vertical (85 degree slope). The CD 162 crown has a narrow, rounded, sloping crown ("narrow shouldered"). The skirt of the Star CD 162 has more incline (approx. 82 degree) and the base diameter is wider than the Star CD 161.

CD 162

The CD 162, referred to as a " deep groove, double petticoat", was made for use with insulated drop lines and 6 to 8 gauge secondaries. Several prominent glass companies manufactured the CD162 Star in the early 1900s; Novelty Glass, Sterling, and Harloe (after the move to Pennsylvania). Excavations at the Elmer "lower" works in 1980 produced fragments of Harloe-type Star CD 162 (10).  Current literature lists three embossing index numbers for the Star CD 162:

[010]    Smooth base, single star
[020]    Sharp Drip Point, single star
[030]    Smooth base, two star

Colors range from aqua to dark olive green for the [010] and [030] index pieces. No example of the CD 162 [020] Star has been seen. Three mold styles have been observed:

Wide Dome - Common, smooth base, ½" wire groove, often a ½" star pointing downward. "Elmer Ring" often present.
Figure 20
Figure 20 Wide Dome

Narrow Dome -  Frequently found smooth base, ½" wire groove, one or two 7/16" stars, pointed downward, "Elmer ring" is present.
Figure 21
Figure 21 Narrow Dome

Wide Groove  -  Smooth base, ¾" wire groove, single 7/16" star pointed downward. "Elmer Ring" usually present.
Figure 22
Figure 22 Wide Groove

The narrow dome, wide groove style has been much discussed by various insulator collectors. Some believe that it resembles a wide groove CD 161.2 because of its wide, flat wire ridge. Woodward concurs, however, no such listing is found in the McDougald literature. The assignment of embossing index numbers is made by McDougald. The dilemma has been referred to Woodward and McDougald in 2001. Resolution is pending. Until such time the literature is changed it will be considered a narrow dome, wide groove style as a CD162 [010]Star variant.

CD 162.1

The Brookfield Glass Company catalogue of 1912 describes the style number 36 as a deep groove double petticoat insulator which features a slightly larger wire groove ( 5/8" ) than is usually seen.  The dimensions shown are identical to those of the CD 162.1 Star signal (Figure 23).
Figure 23
Figure 23 CD 162.1

This similarity seems to point to the belief that this Star insulator is not an Elmer product but rather a Brookfield product from the later years. Tibbitts (11) attributes the design to Samuel Oakman's patent # 288360 (Nov.13,1883), however, this patent also covers the earlier Brookfield CD 162. Why the heavier crown and more squared top were designed is unknown. Colors of the Brookfield No. 36 range from aqua through green aqua to dark aqua. This includes the green aqua often found in the CD 162.1 Star.

CD 162.3
A small wire groove insulator, said to be the predecessor of the CD162 (Figure 24),  was intended for use with bare wire or insulated wire smaller than 10 gauge. Only two sources of this piece have been reported: Brookfield and Star. The ice blue, steel blue, gray and light aqua colors suggest Harloe production while the dark greens are a Brookfield type of glass.  McDougald assigns two embossing index numbers to the CD 162.3 Star:

[010]    Single downward pointing star, smooth base
[020]    Two, downward pointing stars, wedge shaped drip points
Figure 24
Figure 24 CD 162.3

Close examination of these insulators reveals at least six mold variations. The variations, although minor, should be considered. The variations are:
Figure 25
Figure 25 Left, Dot on dome variant, Right, Very rounded groove variant
  • Raised dot on dome, large star (5/8")
  • Raised dot on dome, small star (3/8")
  • Raised dot on dome, large star very rounded lower wire groove edge
  • Small star
  • Large star, very rounded lower wire groove edge
  • Large star          
CD 164

A double petticoat insulator, referred to as an "Extra Deep Groove D P Signal" was made by several glass companies for use with ¾" cable, electric street lighting, and street railways. Brookfield, Hemingray, Sterling, Harloe, and possibly others marketed this insulator under a variety of model numbers. A 1904 GE equipment catalogue shows an extra deep groove insulator as # 9311.  Brookfield made them as # 487. Harloe, in 1907,assigned all patents to Brookfield. When Sterling moved to Hawley, the Harloe Insulator Company was already making CD 164 insulators embossed HICO. The retooling of the molds to show a Star would have been a simple task. McDougald (12) shows a CD 164 Star and assigns three embossing indices to it:

[010]    Single Star, smooth base       
[020]    Single Star, sharp drip points      
[030]    Single Star, smooth base, blotted out circle on rear skirt

The colors range from aqua through green to dark olive green. The [020] embossing insulator is reported as being only in aqua. The [030] Star has not been verified, there is, however, a Brookfield CD 164 with off-center B embossing and a circular blot out in mid rear skirt. Three mold variations have been observed:

Round Dome - This single star shape with darker green colors and nearly vertical skirts suggests Brookfield origin. The dimensions and characteristic round dome compare to the Brookfield #38. The slight rounding of the lower wire groove edge is consistent with the "soft edge" trait found in many Brookfield insulators.
Figure 26
Figure 26 Round Dome

Oval Dome - Features a slightly oblong dome ridge. Found in both with and without drip point models in darker aqua shades. The soft edge and color suggest Brookfield glass. This same oval dome is seen on the Starling and Harloe CD 164 insulators suggesting Sterling manufacture either at the lower Elmer works (1902-03) when Sterling was taken over by Harloe. An "Elmer Ring" is sometimes present.      
Figure 27
Figure 27 Oval Dome

Round Edge - A round dome, smooth base variation with colors is predominantly blue aqua. The identifying characteristic of this variant is a downward curve of the lower wire groove edge where where it joins the base (similar to the HICO pieces). There is a noticeable widening of the base. No" Elmer Ring" is present.      
Figure 28
Figure 28 Round Edge

CD 185

This mold style was created to provide insulation for low voltage applications found in mines. At the start of the twentieth century, there was a growing market for such insulators in the growing numbers of gold, silver, copper coal, etc. mines.  Only four suppliers of note are known to have made CD 185 insulators (Figure 29): Brookfield, Hemingray, Jeffory, and Knowles. Knowles is known to have sold products from other factories, including Brookfield (13)
Figure 29
Figure 29 CD 185

Hemingray made insulators for the Jeffory Mining Company (14).  Current price guides indicate only one embossing index numbers for CD 185 Star mine insulators [010]. In reality, there are slight variations in dimensions.  The insulator has a threaded pin hole, smooth base and is made from a two-part mold. Colors range from aqua to shades of green which suggest either Brookfield or Hemingray origin.

CD  200

Telephone systems usually required a "Transposition Insulator" such as the CD 200 (Figure 30). The concept of two wire grooves and two storm shields with one skirt between  the grooves was first introduced by N. Rousseau in 1883 pat# 289,499. His design underwent several changes before becoming the present CD 200 transposition.   N.R. Woodward identifies Brookfield as being involved with the CD200.
Figure 30
Figure 30 CD 200

There may be other unknown manufacturers.  Letters of patent (520,367) were issued to Fred Locke in 1894 covering a"Transposition Insulator."  Because of an earlier contract with Brookfield to make his glass insulators, it could be assumed that Brookfield made his transposition as No. 52. A side-by-side comparison of the Brookfield #52 and the CD 200 Star shows them to be identical  thus, Brookfield appears to be the likely manufacturer of the CD 200 Star.  Colors generally range from blue aqua through light green to yellow green. The glass appears relatively free of impurities and tends toward greenish colors such as found in Old Bridge Brookfield products.   Embossing index number [010] is used to describe this one-piece, smooth base piece. A small (3/8") star, pointing downward, is found on the skirt. There is no "Elmer Ring".

CD 260 

The CD 260 cable insulator traces its origin to the efforts of Samuel Oakman (pat# 430,296 dated June 17,1890). This unique insulator (Figure 31), called the "Roman Helmet" (not to be confused with the "Mickey Mouse" or "Viking Helmet") was designed to insulate heavy wires or cables and to serve as a temporary holder for heavy wire. It is also used in making turns.  Two embossing index numbers are used:     

[010]    Large (5/8") downward pointing star, smooth base         
[020]    Large (5/8") downward pointing star on front skirt, embossed "PATENTED, JUNE 17, 1890" on rear skirt, smooth based.
Figure 31
Figure 31 CD 260

The only recognized makers/users of this insulator style are the California Glass Insulator Company and the Harloe Insulator Company. It is thought that the Harloe works produced  the CD 260 Star insulators for a time, using reworked Sterling molds. California glass was a darker, more complex hue ( purples, smoky rose, dark plum, blue green, etc.). Two mold styles of the California CD 260 were produced: "wide" groove" and "pinched" groove. California Glass was not known to or suspected of producing CD 260 Star insulators. The blue-aqua through light green to darker green glass color of the CD 260 Star appear consistent with the Harloe glass of Hawley, Pennsylvania. The darker colors probably resulted after the 1907 assignment of patents to Brookfield.

Tie Down     

Some collectors gather glass insulators because of their variety, form and/or symmetry.  Others appreciate the color variations of sunlight on the insulators in their windows or out on the cross arms. The Star collector, however, gathers a part of history.  These Star insulators were a basic part of the communications and power industries entry to the 20thcentury.

*  *  *  *  *
(1) N. R. Woodward, 1988 Report, Glass Insulator in America

(2) John W. Hammond, 1941, Men and Volts-The Story of General Electric

(3) Maurath, 1990, New England Manufacturers Chapter of History and Guide to North American Glass Pin Type insulators, John McDougald

(4) C. McDougald, 1999, Crown Jewels of the Wire, A conversation with William L. Brookfield, December 1999

(5) McDougald,1990, History and Guide To North American Glass Pin Type Insulators, vol. 1, California Glass Insulator Company, pg.90

(6) John C. Tibbitts, A Guide For Insulator Collectors,vol. 2,1968,item 2-96

(7) Marion C. Milholland, Most ABout Glass Insulators, 1972, pg. 28

(8) The Elmer Times, December 11, 1903 edition

(9) R. Klingensmith, McDougald vol. 1,Glass making in Elmer at the Turn of the Century

(10) R. Klingensmith, McDougald vol 1,Glass making in Elmer at the turn of the Century

(11) John C. Tibbetts, A Guide For Insulator Collectors, Vol.1,1967, item 47

(12) McDougald,1990, History and Guide to North American Glass Pin Type insulators, vol.2

(13) N.R.Woodward, 1988 Report, The Glass Insulator in America, pg.43

(14) McDougald, 1972, History and Guide to North American Glass Pin Type Insulators, vol. 1, pg. 147

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