It's been established that one could invent microscopes early with a magnification of up to 1500x.

It occurred to me, though I really know nothing about this, that putting metals under a microscope could lead to a better understanding of their structure, and therefore better metallurgy. It might even lead to the knowledge that carbon is the key to making steel. (At 1500x you obviously couldn't even get close to the individual atoms, but maybe something in the structure would suggest the addition of a new ingredient.)


I haven't yet decided what level of magnification my world has been able to achieve, but for this question assume something between 275x and 1500x. Also assume some clever scholars with motivation to observe metals of different types and even at different heats. I'm most interested in iron and bronze, and the carbon question, but I'm interested in any application to metallurgy.

Finally, I should mention that while the technology of this world doesn't have a straightforward analogue to our own, most everything besides some of the chemistry is pre-Renaissance. This question represents one step in determining the world's metallurgical knowledge.

Just a quick note, despite my past questions this particular one does not involve pyromancers, and of course does, as stated, involve iron.

  • 2
    $\begingroup$ Of note: Even with today's technology, alloys are still something of a dark art - we don't understand the processes well enough to predict if a new technique is going to create a good steel. $\endgroup$
    – Pingcode
    Feb 17, 2018 at 11:36

2 Answers 2



Metallurgy and iron casting are way more than just observing with microscope. Yes, with a microscope one can observe the grain shape and size, but those alone are of little help without a proper model explaining what is happening that results into different grain shapes and the ability to understand the alloy composition.

Preparing a sample for metallography requires:

  • proper grinding
  • treatment of the polished face with suitable solution (different solutions etch and expose different aspects of the sample, i.e. some make grain borders more visible)
  • ability to consistently produce the very same alloy (else the chances of a systematic study are low)

Also keep in mind that empiric knowledge on how to make good steel was already developed way before the invention of microscope (think Damascus steel or katana), and even after its invention there was no immediate improvement on metallurgy (though we had some pretty brilliant people inventing gravity, calculus and electromagnetism).

To really improve metallurgy you need advancement in chemistry and physics, to the point you are able to figure out that spacial arrangement of atoms can influence the properties of the material.

Example: if you want to make a piece of metal hard on the surface but though in the core (think of a sword or a gear), you need to be able to correlate the content of carbon to the hardness and toughness (the more the carbon the more the hardness and the brittleness), and if you are able to model the diffusion of carbon with temperature and time you can come to invent a proper treatment that can lead to the desired properties.

  • $\begingroup$ Good stuff in the first paragraph, but for the second remember the microscope has come very early in this world, essentially in the Classical era. I'm not saying anywhere that you need a microscope to get good steel, just asking whether or not a culture that hadn't yet might if they were inclined to experiment with microscopy. Still, +1 $\endgroup$
    – Random
    Feb 17, 2018 at 4:43
  • $\begingroup$ And of course this answer, while very helpful, also leaves out details on the difficulty sample preparation and doesn't go into whether observing grains might eventually lead to such a model. I'm guessing no, but I think it's a question worth asking. $\endgroup$
    – Random
    Feb 17, 2018 at 4:47

I agree with L.Dutch that there is much more to metallurgy than observations with a microscope. But I also believe there is merit to a scenario where early access to a microscope leads to accelerated understanding of steel composition. Through repeated observation by motivated scholars I believe it is conceivable that an understanding could be formed of basic alloying (iron/carbon, copper/tin etc), and basic heat treating. I do not think it outside the realms of feasibility that a simple microscope could have a large impact in this area.

  • $\begingroup$ with just a microscope there is no way you are going to discriminate between how carbon and iron are arranged in quenched steel and in cast iron, no matter how many time you look at it. $\endgroup$
    – L.Dutch
    Feb 17, 2018 at 6:24

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