Definition of "specific heat"

[JOM]

Here's a more serious example of miscommunication on a technical topic.

I heard an expert witness in a major trial asked to define "specific heat".

He answered that specific heat is the relative measure of a body to give off heat.

Now that's not correct, is it? Specific heat is a precisely defined technical term. Perhaps he was trying to dumb it down for a lay audience. Nobody challenged his definition.

Cheers,
John.

 

[TBP]

"Specific Heat - The capacity of any substance for receiving heat as compared witha another which is taken as a standard, this being generally water. Thus, the same quantity of heat which will raise one pound of water 1*F will raise about 4-1/4 pounds of cast iron 1*F, so the specific heat of water being taken as 1.000 that of cast iron is 0.241."

Hawkins Mechanical Dictionary - 1909.

 

[JOM]

Hawkins again!

What's he say about E=mc2 ? Cheers,
John.

 

[JOM]

Hawkins: "heat capacity is the capacity of any substance for receiving heat.."

That's so fundamental and simple it's surprising. It also matches in an inverse way what the expert witness said. He talked about a body's capacity to give off heat. But that depends on several factors like temperature differnce and thermal conductivity and heat transfer coefficients. To me, it's the amount of heat required to raise a unit mass by a unit degree in temperature (expresseda as a ratio compared to H2O).
Cheers,
John.

 

[TBP]

One of the most interesting things I've found in the old Hawkins dictionaries (there's a mechanical and an electrical, both published in 1909) is a definition for fax machines. "Facsimile telegraphy". And the definition describes the exact same function as fax machines now.

 

[abeltio]

no wonder tbp... fax is short for facsimile. the word facsimile was too long for the regular office fauna ;-)

 

[TBP]

abeltio - I'm old enough to remember the term "...or reasonable hand-drawn facsimile".

The old Hawkins dictionaries were not "cutting edge", but rather aimed primarily at tradesmen, so I have no doubt that the fax technology existed before 1909. I've heard about a dedicated one that transmitted financial information between Switzerland and London England around 1900, but haven't actually read anything about it. I'm curious as to just how old the technology is. Anybody know?