> But Mr. O’Grady must have been the first writer to seriously consider the physics of the miniature.

Railway modelers (and probably ship modelers before them) were in this domain before that. Real water doesn't look right on a model layout. Also things like the practical dimensions of the rails and the speed at which things move. The scaling of the physics is important for a live steam model, as it affects the operation as well as the physics.

Apart from that, scale models were a primary engineering tool before the advent of computer simulation [1]. Models are still used for training ship pilots [2], and these models must account for how physical properties scale.

[1] https://onlinelibrary.wiley.com/doi/book/10.1002/97834336096... [2] https://www.portash.com.au/