Civil War Era
Telegraph Insulators

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One of Ted Wagner's many endless questions, when he first started learning about telegraph during the Civil War was, "what kinds of insulators were used?"  This page will to address this question.

This explanation is short primarily in that the proof is in the patent.  The patent for the threaded insulator wasn't granted until July 25, 1865.  Louis A. Cauvet invented this insulator.  The idea itself was developed, not in its entirety, by the Brookfields.  Cauvet visited the Bushwick Glass Works company later in 1865 with an example of his invention.  The Brookfields liked Cauvet's idea and bought patent no. 48,906 and shortly there after, began producing a threaded insulator.

Our timeline is quite definite.  The Civil War ended in April of 1865.  Cauvet's invention of a threaded insulator wasn't patented until July of 1865 and production of a threaded insulator didn't take place until later.  So, what kind of insulator was used?

Using a reference written by David and Marilyn Delling combined with photographs taken during the Civil War, we can better determine what insulators were used.  Primarily, glass insulators were the insulator of choice during the Civil War.  Iron hook insulators, what we now call "ram horns", were also used.  However, we find mention of their dislike in Prescott's book "History, Theory and Practice of the Electric Telegraph".  It was thought that the iron in the insulator attracted lightning.  What they were not able to yet distinguish is that although the iron was embedded in a wood block and attached to the telegraph pole, the wood block and the pole it was attached to was a much poorer insulator than a glass insulator mounted on a wood pin. 

Iron hooks and threadless glass insulators were the preferred insulators of the time. More than likely, this is due to their abundance in production. Below you'll see photographs of insulators used in the Civil War.  There will always be a debate about what insulators were used by who.  Primarily, iron hooks and threadless glass insulators were used by the civilian telegraph companies and the USMT (since it was run by civilians).  The flying telegraph, operated by the Signal Corps for a good portion of the war, used wood lances.  From their description in both William Plum and Willard Brown's book, we know these had no further insulation since the wire was gutta percha covered wire.  The lances were 12 and 10 feet in length and had notches cut into them for the wire. 

This collection of insulators were common around the Civil War era.  The iron hook or "ramshorn" insulator was used throughout the western United States due to the conditions of the climate for many years past the Civil War.  Some were still found in service in the 20th century.

There has been much discussion about the use of insulators during the Civil War by the USMT.  As with all wars and economic hardships in the states, the logical hypothesis is that the USMT used what was readily available.  We don't know exactly what was used.  More than likely, what was used for insulators was what was available in the region.  Glass insulators and iron hooks were most likely used.  Iron hooks would have been very useful if temporary lines were erected where iron wire was used.  Iron insulators were nailed to trees in many areas by the telegraph companies, I'm sure this practice was also used by the USMT as those individuals also worked for the railroads and telegraph companies. 

 

Photo/Image

Information

Patent for the Farmer-Batchelder insulator.  Commonly called the "ramshorn" or "iron insulator".  Patent number 21,492, dated 14 September, 1858.
Page 2 of the Patent for the Farmer-Batchelder insulator showing the drawing.  Commonly called the "ramshorn" or "iron insulator".  Patent number 21,492; dated 14 September, 1858.  Item to note specifically in this picture is figure 6, the view looking DOWN a telegraph pole.  This shows the relation of the hook (circles) and how the block was fixed to the pole.
Iron hook insulator or ramshorn owned by Ted Wagner.  This appears to be an improved version of the one patented or from a different manufacturer.  Note the piece coming up from the base in the middle.  The opposite side appears to have broken off.  More than likely, this facilitated the ability to screw these into the wood blocks.
Same iron hook insulator but from the opposite side.
A good close-up of an iron insulator with block and original nails.  This iron insulator is of a different manufacture than the one shown above.  Note the nails and the shape of the block
Same as two above
   
   
This insulator was up for auction on ebay (January of 2003).  This particular insulator with pin is a very hard find.
Same insulator as above.  However, note the burlap or linen which is on the pin to help keep it secure.  Tar and other adhesives were experimented with in helping keeping the insulator on the pin.

Photo subtitled: "Title Cutting telegraph wire and connecting the ends, so that the point at which the connection is broken cannot be seen from the ground."

This photo shows hatpin insulators as shown above.

Source:
National Archives  NWDNS-77-F-194(6)(62), ca.1862-ca.1863
Photographer, Russell, Capt. Andrew J.
Threadless insulator.  Note the small skirt at the bottom compared with the hatpin above.
Same insulator as above, but from the underside.
Again, same insulator as above.  Note the quality of the glass.  Reproduction insulators typically have a much clearer glass.
This is a mulford insulator.  Commonly used in Canada.  This is a threadless insulator as well.  Note the large skirt as well as a large pin-hole.  You can see the difference through the glass.
Same insulator from the underside.  As with many old insulators, this one is damaged at the bottom.
This insulator is commonly referred to as an "egg" insulator due to its shape.  These were common in the south and are very difficult to find.  The several pictures below show you different insulators of the same kind but of different shape and condition.  Some are melted.
  
This photograph is of the side of Libby Prison in Richmond, Va.  The telephone poles are at the edge of the street.  The close-ups below of the pole in the left foreground show what the egg insulators looked like on the poles.
    
This first picture shows a good profile
 
This third picture is a good close-up and you can see the profile of the insulator quite well, although at this resolution, it's a bit blurry. 
  This photograph is from near Chattanooga, Tennessee.  Again, in the close-ups, you can see the shape of an egg insulator.
This photograph is also from near Chattanooga, Tennessee.  This is an excellent photograph from the period and clearly shows a "tophat".
This photograph is from near Berlin, Maryland; (now Brunswick). From the location, and knowing that there is a pontoon bridge here, this more than likely is from a USMT installation.  Close-up is hard to tell, could easily be a "tophat" insulator or a big "egg" insulator.
This photo from Atlanta, is by far probably the most insightful photo I've found.  This clearly illustrates that, as is often the case, whatever was available is what was used.  Note both "egg" and "tophat" insulators.
  

 


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