Who developed the Higley Invention?

I bet it was someone called Kadiddlehopper.

1) Which Higley invention do you mean? I researched this and I did not find anything that would be commonly known as the "Higley invention".
There are certainly various people called Higley, and some of them have invented something.

For instance Rolland C. HIGLEY: "Higley sought a patent on a tractor-drawn frame or subsoil tiller"
http://ftp.resource.org/courts.gov/c/F2/387/387.F2d.855.20779_1.html


2) "Professor of English Sarah Higley says creating languages is a more common pursuit than many people might suspect. She would know: She’s the inventor of the language Teonaht, a board member of the Language Creation Society, and a member of an online Listserv of more than 500 people—linguists, computer scientists, mathematicians, humanities scholars, and others—who create languages for fun. They call such languages “constructed languages”—or conlangs—and pursue their hobby as an art form that can be enjoyed for its sounds, its script, or, for real aficionados, its grammatical structure."
Source and further information:
http://www.rochester.edu/pr/Review/V72N4/04_features01.html

"The Lingua Ignota, "brought forth" by the twelfth-century German nun Hildegard of Bingen, provides 1012 neologisms for praise of Church and new expression of the things of her world. Noting her visionary metaphors, her music, and various medieval linguistic philosophies, Higley examines how the "Unknown Language" makes arid signifiers green again. This text, however, is too often seen in too narrow a context: glossolalia, angelic language, secret code. Higley provides an edition and English translation ofits glosses in the Riesencodex (with assistance from the Berlin MS) , but also places it within a history of imaginary language making from medieval times to the most contemporaryprojectsin efforts to uncover this woman's bold involvement in an intellectual and creative endeavor that spans centuries."
Source and further information:
http://www.rochester.edu/College/ENG/news_books.html