Many years ago,  there was an article (in Popular Electronics?) that needed a very high value resistor.  They built it by drawing a line between two terminals with Higgins India Ink.  No idea if the ink is still made the way it was 50 years ago...

I made a high-value resistor using motor oil and a couple of stainless
bolts. It worked for what I was doing (testing an HP-425A
Microvolt-Ammeter) but calculated as only 8,500 Megohms.

Jeremy

On Sat, Mar 24, 2018 at 10:18 AM Mark Sims holrum@hotmail.com wrote:

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Sent from my iPad 4.

On 24 March 2018 at 17:34, Jeremy Nichols jn6wfo@gmail.com wrote:

I had some discussions some time ago about using oil as a dielectric in a
capacitor with someone at NPL. He said the loss of both cyclohexane and
Polydimethylsiloxane (PDMS = silicon oil) is very low. He said the only way
I would measure the loss of them was a resonate method, and detecting small
changes in Q. My thoughts on putting them as the dielectric in a capacitor
and measuring on an LCR meter would not work, nor would my transmission
line. I had already satisfied myself that using a coaxial probe and VNA
would not work.

As he said, cyclohexane is nasty stuff, but PDMS is much more
environmentally friendly.

Dave