The pants of a prizefighter....

[Professor J. Cogsworthy]

Anyone here know what kind of material this type of pants was made from?

[Heckler]

They were made from the scrotums of Rhinos, all killed with a single punch from the pugilist who proudly wore them*

*The above may not be entirely true.

[Mr. Boltneck]

At a guess, those fighting trousers are probably a knit wool. Pre-Spandex cycling shorts used a light, stretchy knitted wool fabric that worked fairly well, and was surprisingly comfortable.

[frances]

Not knitted by hand but on a knitting frame - a machine that may have been worked by hand or later by an engine.  So very steampunk.

[Keith_Beef]

At a guess, those fighting trousers are probably a knit wool. Pre-Spandex cycling shorts used a light, stretchy knitted wool fabric that worked fairly well, and was surprisingly comfortable.

Not knitted by hand but on a knitting frame - a machine that may have been worked by hand or later by an engine.  So very steampunk.

Sounds a lot like what we would call "jersey" cloth: machine knitted cotton, like you would use to make T-shirts.

[Professor J. Cogsworthy]

http://www.naturesfabrics.com/wool-fabric/interlock/1-2-yard-97-merino-wool-3-spandex-wool-interlock-blend-feltable.html

Like this?

[montysaurus]

Material similar to the kind used for making Union suits. A cotton knit.

[montysaurus]

A cotton knit.https://www.fabric.com/apparel-fashion-fabric-knit-fabric-jersey-knit-fabric-solid-cotton-cotton-blend-jersey-knit-fabric.aspx Like the Fabrics here.

[frances]

It is the same machine that they used to knit silk stockings on.  So a very, very fine knit.