17/32 Inch Scale

From LBSC, The Modelmaker, Volume 7, Number 4, April 1930:

I had better explain that as I have had more to do with 2-1/2 inch gauge locomotives than all the rest of the sizes put together, I will talk chiefly about this favorite size; but want to point out that it is NOT "half-inch-scale" but much larger. A half-inch-scale locomotive should run on a track of 2-3/8 inch gauge only. A 2-1/2 inch gauge engine is roughly 17/32 inch or 13 mm to the foot, and stands nearly 5/8 inch higher than a 1/2 inch scale engine, and is of course longer and wider in proportion. Therefore, brother loco-men, don't waste valuable space by cramping a 2-1/2 inch gauge engine into 1/2 inch scale load gauge. Such a job viewed from the front makes you think of a bulldog standing with is legs straddled out.