Am 31.03.2022 um 09:14 schrieb JanPB:
> On Wednesday, March 30, 2022 at 11:04:11 PM UTC-7, Thomas Heger wrote:
>> Am 30.03.2022 um 20:08 schrieb JanPB:
>>
>>>>>>>> But I have not dealt with these equations, because I disliked Einstein's
>>>>>>>> subtraction of magnetic field strength from electric field strength, anyhow.
>>>>>>>
>>>>>>> It's nothing peculiar to Einstein, it's the Gaussian system of units.
>>>>>> I have actually problems with subtracting electric field strength from
>>>>>> magnetic field strength.
>>>>>>
>>>>>> This is like subtracting 1 V from 1 A.
>>>>>>
>>>>>> To me this doesn't make any sense at all.
>>>>>
>>>>> That's your problem then. If you want to resolve this, you must
>>>>> learn how various systems of units work.
>>>> No.
>>>>
>>>> In the cgs system electric field strength and magnetic field strength
>>>> have the same unit of force, because the fields were equated with the
>>>> process of measuring them.
>>>>
>>>> These measuring devices contained deformable springs, which measure a force.
>>>>
>>>> Such springs are contained in many analog measuring devices, like a
>>>> pressure gauge, a cithen balance or a volt-meter.
>>>>
>>>> All of them measure something by a reference to a deformable spring.
>>>>
>>>> But you cannot subtract Volts from psi, just because both were measured
>>>> with a deformable spring.
>>>>
>>>> To do so would require a physical justification, which was entirely
>>>> missing in Einstein's text.
>>>
>>> No, this is how units of systems work (Gaussian, in this case).
>> I have given you already the example, that many anolg measuring devices
>> work with deformable springs, which emasure ultimatively a force.
>>
>> But still you must not add or subtract different units,
>
> They are not different units in the Gaussian system.
>
>> like pressure
>> and weigth,
>
> N/A. Learn about X if you want to discuss X (esp. if you want to
> criticise X).
>
>> for instance, even if a pressure gauge and a kitchen scale
>> work with a spring.
>>
>> It is fantastically stupid nonsese to even advocate such use of values.
>
> No. You simply don't understand how this works. Some people, when
> they don't understand something, tend to blame everyone but themselves
> for this. I cannot fix this problem for you.

I understand, that magnetic field and electric field have different
effects, hence are different things, even if related.

So: I cannot subtract 1 amp from 1 Volt, because that does not make much
more sense then subtraction weigth from pressure.

Both fields are related, but actually different things.

Now Einstein used magnetic field strength in the z-direction callen 'N'
and subtracted an electric field strength called 'Y' from that (times a
real valued factor v/c).

I have asked the question, how this equation is related to physical reality.

Now you replied, that electric and magnetic 'force' have the same units
in the cgs system (these units are called 'dyne') and therefore might be
subtracted.

To me this is total nonsense. Actually the term 'force' was already
wrong, because actually meant was 'field strength'.

That 19th century physics didn't know better would not count as an excuse.

>>> But you haven't answered my question why exactly the same
>>> addition or subtraction does not bother you when it's written
>>> in the Lorentz force law:
>>>
>>> F/q = E + (v/c) x B
>> Actually it did bother me, that Einstein tried to subtract electric from
>> magnetic field strength,
>
> So why it doesn't bother you when Lorentz does exactly the same?

Lorentz and his books and papers were not my topic.

If Einstein wanted to incorporate some parts from Lorentz' works into
his own paper, he had to write quotes (what he didn't).

>> Einstein had not used the 'x' of the cross product correctly,
>
> The point is that the components of the Lorentz force law formula
> look exactly like those of the Lorentz-transformed E and B fields.
>
> "Einstein had not used the 'x' of the cross product correctly" is,
> incidentally, the funniest part of your post.

Here we use an 'ACII only' medium, hence that cross is written as 'x'.

Actually it has a different code in ASCII extensions, but I prefer to
stick to 'ACII only'. That's why 'x' is an ASCII letter, which
occasionally means the cross from the cross product and not the letter x.

>>>>> The values of the fields measured by the k observer.
>>>>> Ultimately they are the way they are because Maxwell's equations
>>>>> are the way they are.
>>>>
>>>> I wouldn't count that as an explanation.
>>>
>>> That's where the formula comes from. Can't you derive it for
>>> yourself?
>> Actually I have read a book of Maxwell and was not able to find the
>> equations Einstein used.
>
> The transformed E and B fields were derived by Lorentz, not Maxwell.
> Einstein only re-derived them to demonstrate the power of his new approach.
???

Actually Maxwell was the guy, who developed the equations, that were
named after him, not Hendrik Lorentz half a century later.

>> So, he had apparently other sources, but didn't consider it necessary to
>> inform the reader, which his sources were.
>
> It's obvious what his sources were: Lorentz's big paper from the
> previous year.

'Obvious' is an illegal phrase in theoretical physics.

>>>>> He only wanted to show that his method yields the same formulas
>>>>> for the transformed fields as those obtained by Lorentz. He also
>>>>> does it more elegantly by being able to get rid of the extra multiplicative
>>>>> factor by quick geometric considerations while Lorentz works quite
>>>>> hard on that one detail in his 1904 paper.
>>>> Here a quote from some text written by Lorentz would be required.
>>>
>>> If it was a textbook, yes. In a research paper devoted to a topic everyone
>>> is talking about - no. It's excessive pedantry in most contexts of this type
>>> and considered a defect by some.
>> Don't you think it would be nice to know, WHICH textbook Einstein used?
>
> No. This is a research paper, not a textbook. The reader knows exactly
> where the previous stuff comes from.

'Textbook' is not meant as equivalent to 'book printed on paper'.

I prefer the simple phrase 'text', which is applicable to any kind of
written material, on whatever medium.

>>>> If he actually wanted to do, what you assume he wanted to do, he had to
>>>> write that himself.
>>>
>>> Not needed, he was writing for the professional audience. Another author
>>> might have said it. Point is, this is a non-issue. Even less than non-issue.
>> I think, it is in fact an issue!
>>
>> Actually Einstein mentioned Heinrich Hertz and his adaptation of
>> Maxwell's equation.
>>
>> As far as I can tell, Herth did that and developed an own form of
>> Maxwell's equations. But Hertz died young and his version got more or
>> less lost.
>>
>> Now it is hard to say, to what Einstein actually referred with his
>> equations.
>
> Einstein just wrote Maxwell's equations.

'Maxwell's equation's' (as we know them today) were actually not
written by Maxwell himself.

The origional 20 quaternion equations of Maxwell were altered by a guy
named Heaviside after Maxwell died.

Such equations should therefore bear the name 'Heaviside equations'.

Einstein menationed 'Maxwell-Hertz equations', but didn't regard it
necessary to inform the reader, from where he got them.

So we are now forced to estimate, to which equations he actually referred.

Since Heinrich Hertz was mentioned, he meant something like 'Hertz
equations', which Hertz had apparently published somewhere.

Since his works are far less 'obvious' than Maxwell's, we need a
reference to the meant source. But this was missing here as in all other
cases.

Now you argue, that this is actually obvious to the intended audience of
professional physicists.

Therefore you should be able to tell me the source and provide a
reference to the quoted material.

>> I have read, the Hertz Ansatz used total derivatives, while Einstein
>> wrote partial differential equation.
>
> This is irrelevant.

Not at all.

If the 'Hertz ansatz' is actually quoted correctly, than everything is
ok, otherwise not.

....

TH