How did H.K. Onnes measure temperature and resistivity?

[DariusP]

How did H.K.Onnes measure temperature and resistivity?

As you know, Onnes is a dutch physicist that was the first person to liquefy helium and discover superconductivity a year or so later. I am wondering - what equipment was he using at that time? I couldn't find this information anywhere. Even nowadays measuring cryogenic temperatures is a huge challenge and I'm sure it would require expensive equipment.

 

[ZapperZ]

How did H.K.Onnes measure temperature and resistivity?

As you know, Onnes is a dutch physicist that was the first person to liquefy helium and discover superconductivity a year or so later. I am wondering - what equipment was he using at that time? I couldn't find this information anywhere. Even nowadays measuring cryogenic temperatures is a huge challenge and I'm sure it would require expensive equipment.

Did you come across this already?

https://www.lorentz.leidenuniv.nl/history/cold/DelftKes_HKO_PT.pdf

Zz.

 

[DariusP]

Did you come across this already?

https://www.lorentz.leidenuniv.nl/history/cold/DelftKes_HKO_PT.pdf

Zz.

I have and it seems like he used a gas thermometer but is a gas thermometer really this accurate? At one point in the article he mentions that "the resistance of a platinum wire become constant at temperature of 4.25K". Can a gas thermometer measure temperature to a such degree of accuracy? I've never personally used it.

 

[ZapperZ]

I have and it seems like he used a gas thermometer but is a gas thermometer really this accurate? At one point in the article he mentions that "the resistance of a platinum wire become constant at temperature of 4.25K". Can a gas thermometer measure temperature to a such degree of accuracy? I've never personally used it.

If it says that, unless you have other evidence to the contrary, then that was what it was.

Zz.

 

[DariusP]

If it says that, unless you have other evidence to the contrary, then that was what it was.

Zz.

I do not see any information on how the resistance was measured though.

 

[Vanadium 50]

Where are you going with this? Resistances have been measured for decades before this - c.f. Ohm's Law.

 

[DariusP]

Where are you going with this? Resistances have been measured for decades before this - c.f. Ohm's Law.

Well, if speaking about temperature, for example, a thermocouple starts to show high errors after -50 degrees of celsius and below. Not a reliable tool for cryogenic temperature measurements, basically. I've read, however, that Onnes used a gas thermometer. Perhaps it is reliable, I don't know. Now I am wondering what reliable tool did he use for resistance measurements...

 

[Vanadium 50]

I don't know what he used. But there is no reason to suspect unreliability because of cold, because the entire resistance measurement can be warm. In the simplest form, you have a battery and an ammeter in series with the cold thing you are testing. It's more likely that something more like a Wheatstone bridge was used, but in any event, you can always make this measurement warm.