From the above paragraph one could almost assume Keely is saying any other mode of vibration than Longitudinal is differentiated; i.e., Shear or Transverse and Love, Lamb and Raleigh are all differentiated chords but the Longitudinal is harmony. In certain ways this makes a lot of sense. Refraction (differentiation) is based on angle of incidence and one assumes Keely's differentiation is the same. It is important to note that as the angle of incidence changes so too does the frequency. This principle accounts for many things such as the range of colors in a rainbow (refracted light at different angles) as also vortex motion.

"The velocity of the vibration governing the flow of the magnetic stream, comes under the head of the first interatomic, and ranges from 300,000 to 780,000 vibrations per second, the first order above odor permeating the molecules, of the glass plate of the compass (with the same facility that atmospheric air would go through an ordinary sieve through which it passes) to arouse sympathetically in the needle the concordant condition that harmonizes with its own. The course of this sympathetic flow is governed by the full harmonic chord, and consequently moves in straight lines, thus transmitting its sympathy free of molecular interference." [Keely, ANSWERS MADE IN LETTERS FROM MR. KEELY - TO QUESTIONS ASKED OF HIM]

See Also

Angles of Incident of Etheric Sympathetic Streams
ANSWERS MADE IN LETTERS FROM MR. KEELY - TO QUESTIONS ASKED OF HIM
Differentiation
Refraction