Locke: Hemingray or Brookfield?
The Insulators
Left to Right, Top to Bottom: 
 
Row 1: 
 - CD 287.2 BROOKFIELD [020],
     Wide dome variant, Aqua
 
 - CD 287.2 LOCKE [010], Gray
 
 - CD 287.2 LOCKE [010], Gray
 
 - CD
     287.2 BROOKFIELD [010], Narrow dome variant, Light Aqua
 
 
Row 2: 
 - CD 287.1 LOCKE [010], Red
     Amber, No Extension
 
 - CD 287.1 LOCKE [010], Peacock
     Blue, No Extension
 
 - CD 287.1 LOCKE [010], 7-up
     Green, No Extension
 
Row 3: 
 - CD 204 LOCKE [010], Blue Aqua
 
 - CD 204 LOCKE [010], Light
     Aqua
 
Row 4: 
 - CD 287.1 LOCKE [010], Light
     Aqua, Smallest Extension
 
 - CD 287.1 LOCKE [010], Light
     Aqua, Large Extension
 
 - CD 287.1 LOCKE [010], Light
     Aqua, Larger Extension
 
 - CD 287.1 LOCKE [010], Light
     Aqua, Largest Extension
 
Row 5: 
 - CD 287.1 LOCKE [010], Light
     Aqua, No Extension
 
 - CD 287.1 LOCKE [010], Peacock
     Blue, No Extension
 
 - CD 287.1 LOCKE [010], Aqua,
     No Extension
 
 
Copy at the bottom of display is a copy of an advertisement
from the March 4, 1893 Electrical World, showing a CD 287.2, and
advertising the Fred M. Locke & Co. steel pin with cast iron base. 
Some Additional Facts
 - The CD 287.1 LOCKE [010]
     pieces in Red Amber, Peacock Blue, and 7-up Green are known to have been
     manufactured by Hemingray.
 
 - All CD 287.1s, as well as
     the CD 204s, carry the May 22, 1894 patent date
 
 - The "F. M. LOCKE &
     CO." was a partnership that lasted from November 14, 1892 to May 13,
     1895. The "& CO" was dropped from embossings after the
     partnership ended.
 
 - A March 4, 1893 ad (as shown
     at the bottom of the display) depicts the CD 287.2
 
 - A March 10, 1894 ad depicts
     the CD 287.
 
 - There is one CD 287.1 listed
     in the price guide that has a blotted out "& CO".
 
 - There is one CD 287 listed
     in the price guide [070] that has a "& CO" in the embossing,
     not blotted out
 
 - Many CD 287s are listed in
     the price guide with blot outs of "& CO" or "F.M. LOCKE
     & CO".
 
 - The Brookfield CD 287.2s do
     not have a patent date listed, but say "PATENTS PENDING"
 
 - The Locke CD 287.2s have the
     May 22, 1894 patent date, but do not say "& CO" (nor is
     there room in the embossing for a blot out of "& CO").
 
Study Observations
 - The CD 204 insulators were
     mold mates, i.e. made in the same mold
 
 - The CD 287.2 LOCKE insulators
     were mold mates.
 
 - There were several mold mates
     among the CD 287.1s. Some colored specimens matched molds with some of the
     aqua specimens. Some colored specimens matched molds with other colored
     specimens. Some aqua specimens matched other aqua specimens with different
     skirt extension lengths.
 
 - Embossing style matched
     between the CD 287.2 LOCKEs, the CD 204s, and all the CD 287.1s. A number
     of insulators known to have been made by Hemingray were also brought, and
     the embossing styles were compared. Hemingray embossing was consistently
     fine and angular, especially as observed in the "&".
     Brookfield embossing was noticeably coarser and rounder. The CD 287.2
     LOCKE, CD 204, and CD 287.1 embossings were consistent with the known
     Hemingray specimens.
 
 - There were 5 different
     observed skirt lengths for the CD 287.1s. This ranged from no extension on
     all of the colored and some of the aqua specimens, to 4 extension lengths
     on the aqua insulators. Extensions were observed on the light aqua pieces
     only -- the darker aqua pieces did not have extensions.
 
Additonal Observations
 - Paul Greaves reports that ALL
     CD 287s have RB {MLOB} and appear to be Brookfield made. Note that a [070]
     specimen has not been observed and thus may be different.
 
 - Bill Meier reports that the
     CD 287.1 listed in the price guide with a blotted out "& CO"
     may be in error. His records indicate he had reported this insulator, but
     that upon closer examination it is probably an unlisted CD 287 embossing.
 
Conclusions
 - All "& CO"
     embossed units were manufactured by Hemingray, including all CD 204s, and
     all CD 287.1s.
 
 - The CD 287.2 LOCKE was made
     by Hemingray. 
 
Still Up For Debate
The Timeline Originally, it was thought that the CD
287.2 was introduced by Fred Locke around 1893. The narrow dome variant was
probably first, then the wide dome variant with slightly extended middle skirt
was an improvement. The CD 287.1 was introduced some time after May 22, 1894,
and continued in production until around the time of the dissolution of the
partnership in mid-1895. The CD 287 was then produced for a number of years.
However, there are a few problems with that theory: 
 - The CD 287.2 LOCKE does not
     bear "& CO" in the embossing, and does include the May 22,
     1894 patent date. It was obviously made after mid-1894, and probably after
     mid-1895 when the partnership ended. That could mean that it was made
     after production of the CD 287.1s had ceased.
 
 - Ads for the CD 287.1 appear
     well before the patent date in 1894. This would appear to be early enough
     to overlap the supposed introduction of the CD 287.2.
 
 - Many of the presumably
     Brookfield made CD 287s have a blot out of "& CO". Were
     these molds made by Brookfield (which would contradict our theory that all
     "& CO" insulators are Hemingray), or could they have been
     Hemingray molds converted by Brookfield (in which case, why change the
     embossing style while blotting out the "& CO"?)
 
Alternate Timeline CD 287.1 was introduced,
manufactured by Hemingray, sometime around mid 1894. About a year later, Locke
had Hemingray make the CD 287.2. At about the same time or a little thereafter,
Locke switched to Brookfield, and they made the narrow dome variant of CD
287.2. A little thereafter, they made the wide dome variant. Brookfield
obtained the CD 287.1 molds originally used by Hemingray, reworked them into
the CD 287 (causing some blotouts to remain visible), and subsequently
continued to make this shape. There's a couple problems with this theory, too: 
 - A March 4, 1893 ad depicts
     the CD 287.2
 
 - If Brookfield made the CD
     287.2 after May 22, 1894, why didn't they emboss this patent date on the
     insulator?
 
The correct answer is probably neither of these, but some
combination of the two, with perhaps some overlap in production dates. 
Continuing Research
If you have a CD 287 LOCKE [070] (which has the
"F.M.LOCKE & CO" marking, not blotted out), we would love to see
it. Also, if you have a CD 287.1 LOCKE [020] (which has the "&
CO" blotted out), we'd like to see that too. Both of these pieces could
give meaningful clues as to the topics discussed here. 
Many Thanks
to those who contributed insulators for examination, and who
discussed the questions surrounding these insulators: 
 - Andrew Gibson
 
 - Elton Gish
 
 - Paul Greaves
 
 - Bill Meier
 
 - Bob Stahr
 
 - Ron Yuhas