Yesterday, I found an advertisement that was published regularly in the Irish Independent from April till May 1905. As far as I know, this is the only Williams advertisement that mentions the Academy model. The advertisement teaches us a lot about how this machine was marketed at the time (1905):
"Six months ago we commenced selling our well-known WILLIAMS TYPEWRITER No. 2 at a discount of 40 per Cent from the established price. We not only reduced the price but added some new devices, thereby making the machine a little better than before. To distinguish from previous models we call it the Academy Model"
I didn't find similar advertisements in old US papers, but on the internet, I found two pictures of the Williams Academy, made in USA: one on Flickr and the other one in the online Powerhouse Museum Collection.
Ah, and in case you wonder what is Foolscap: here is all you need to know.
Edit: I just received a copy of "Die Schreibmaschine und ihre Entwicklungsgeschichte", written by Ernst Martin (1949), and there it is (p. 129): "1904 erschien eine Neubearbeitung des Modells 2 zum preise von $ 65. Diese Maschine hatte jetzt die Verbesserungen des Modells 4, behielt indessen das dreireihige Tastenfeld bei."