Granby taper tube
As a company started in the 1910's, they were trying out some novel frame details. One was the use of twin down tubes with a "D" cross-section. Chain stays with a square section is another. A more significant innovation was the use of taper tubes in the pursuit of a stiffer frame. It was a single taper, larger at one end and smaller at the other. A modern evaluation might suggest that there was little benefit. In a purely mechanical sense, that is likely true. From a marketing perspective... well, it must have had some value, as they were able to get royalties by licensing the idea. Certainly the idea of shaped tubing keeps showing up, despite some having relatively short lives, thus potentially demonstrating the lack of any true value (personally, this brings some of Colnago's innovations to mind). Maybe the biggest value is the ability to satisfy the customer's desire for novelty??
Steve in Peoria