The carbon rod is from a battery

[Silversmith45]

I found this in a wheatfield where I believe there was a house at one time. It coud be modern or up to 150 years old. I thought that it was a screwdriver handle when I first dug it up, but it gave a metal reading. It appears to be a carbon rod of some sort. It is about 3/4 inch in diameter with ridges down the length. It has gouges from farm equipment over the years. Anyone have any idea what it was used for? Sorry the picture didn't come out better.

[devros]

Is there a hole in it, where a screwdriver could go into it? I haven't seen anything like that used in electronics, but I haven't seen everything either. So maybe it could be a handle of some sort with a little piece of metal in there someplace.

[Silversmith45]

No hole. It's solid.

[devros]

Do you think it could be ferrite? Instead of the carbon, I don't know what carbon was used for, with something like that, it's large.

[Silversmith45]

Originally Posted by devros

Do you think it could be ferrite? Instead of the carbon, I don't know what carbon was used for, with something like that, it's large.

I'm not familiar with ferrite. I woud say that it is carbon, but it seems a little harder than most carbon that I've seen.

[Krom]

If it breaks like a piece of blackboard chalk, I'd say definitely a carbon rod from a battery.
Or, if you'd rather... it's a diamond in it's very early stages.

[Detector]

I found the same thing at the old cycle track. Someone suggested they were carbon rods from old lighting. Carbon arc lamps used in the late 1800's early 1900's.

http://en.wikipedia.org/wiki/Arc_lamp#Carbon_arc_lamp

[Silversmith45]

Originally Posted by Detector

I found the same thing at the old cycle track. Someone suggested they were carbon rods from old lighting. Carbon arc lamps used in the late 1800's early 1900's.

http://en.wikipedia.org/wiki/Arc_lamp#Carbon_arc_lamp

The one at the bottom of the picture looks the same as mine. I wondered about it being something from an old arc lamp. I'm sure the site is old enough.

[Detector]

When I found that bottom one my first thoughts were a screwdriver handle.

[fiat128]

I don't know why but I can't respond on the thread, it keeps asking me to log in (only that thread, no others)

I collect beer cans and the carbon rods are a very common find in old dumps. They come from the old dry cells of the 1930s. There are two styles, the smooth round ones and the the "gear shaped" ones like you found.

They are commonly found with metal detectors too because they have a threaded brass post on the end that a terminal threads onto to clamp down the wire you were attaching to the post.

Here in the desert they are frequently found lying on top of the ground. I pick up the perfect ones when I find them with the idea to make something out of them one day and have dozens of them. They are usually 6"-7" long.

This is the only part of the old dry cell that survives 70 years out in the weather

[fiat128]

I don't know why but I can't respond on the thread, it keeps asking me to log in - Finally got it working!

I collect beer cans and the carbon rods are a very common find in old dumps. They come from the old dry cells of the 1930s. There are two styles, the smooth round ones and the the "gear shaped" ones like you found.

They are commonly found with metal detectors too because they have a threaded brass post on the end that a terminal threads onto to clamp down the wire you were attaching to the post.

Here in the desert they are frequently found lying on top of the ground. I pick up the perfect ones when I find them with the idea to make something out of them one day and have dozens of them. They are usually 6"-7" long.

This is the only part of the old dry cell that survives 70 years out in the weather

[Detector]

Hum? Well none of these have any metal that you can see. Even the smallest broken pieces set the detector off. I'm not sure why dry cell batteries would have been out in this field, because those old motorcycles didn't have batteries. I could compromise and say they could have been carbon rods from batteries that ran the lights for the track?

[Krom]

Well, this is freaky. Look what I found today (6 inches long):

[sofasurfer]

They are carbon rods from batteries. Used to find a million of them in a turn-of-the-century-or-earlier dump (the last century). Some still in remnants of batteries.

[fiat128]

Originally Posted by Detector

Hum? Well none of these have any metal that you can see. Even the smallest broken pieces set the detector off. I'm not sure why dry cell batteries would have been out in this field, because those old motorcycles didn't have batteries. I could compromise and say they could have been carbon rods from batteries that ran the lights for the track?

They are the big round batteries that were used for stuff like radios and flashlights (the kind with a handle that are heavy). These were normal back before todays smaller batteries were invented.

it may be that the detector is picking up reside from whatever they were wrapped in or they have some other conductive qualities to them (they are used in batteries after all). I'll run one under my Ace when I get home and see what happens.

[Silversmith45]

Originally Posted by Detector

When I found that bottom one my first thoughts were a screwdriver handle.

So did I.

[Silversmith45]

I have found carbon rods from batteries before, but they all have been softer than the one I found. This is a hard material.

[randwool]

That's good info. Thanks.

[Billvert]

Just a possibility

I have no idea on the dimensions of these carbon rods:

snip from a WIKI:

I use to operate these prjectors in the 70's-80's before they were replaced by 1500 watt zenon bulbs. Only the lamp housing was changed out, the projector and film part stayed the same. The carbon rods were replaced quite often. The film was split up in about 20 minute reals usually 5 to 6. When it looked like the rod would not make it we would change it. It was a gamble if you had a short real or comercial if a small rod would make it. These ran on a AC to DC motor generator. When I came abord we used a diode unit mutch quiter but the motor-generator where still kept and we could switch over if the diode unit failed. Witch never did in around 15 years. Peerless made the projectors. These were in the bay area California USA

[fiat128]

One other comment about these rods. Modern batteries had them too. The plain "D" cell batteries (like the Evereadys with the 9 lives cat on them) have one in the center. You can find these too. The rod is about 3/8" in diameter and about 3" long.

I've found those with old cruddy battery paste still attached to them.