One of the original writeups on the right triangle geometric-mathematical relationships was to identify a unity metrology system where the speed of light could be defined independently from the earth centric meter and second. The main weakness was that it didn't directly link between that concept and how it can be directly related to the metrology system of SI units. The unity concept is embodied in the elements which describe the values within Figure 6 of the Universal.pdf article.
Universal.pdf now starts out using the SI metrology system and then illustrates how it can transition to a unity type metrology system. It is shown how a unit of time can be mathematically defined in relationship with a mathematically defined speed of light. It is shown how the mathematically defined time unit can be related to any other unit of time, including the SI definition of the second.
On the issue of the "second"-
I personally knew an engineer that was working on the atomic clock for the Global Positioning System, and this before the first satellite was launched. I knew how they had to "fudge" the time duration trying to get close to the value for the earth second. I also know that the current SI definition of the second was "fudged" to get it close a duration of 1/86,400th of an earth's rotation. I do not believe the current SI second is a "fundamental" physical value, it is simply "a very precise definition of the unit of time". I would rephrase the previous quotation (taken from the following URL) to replace 'the unit of time', to 'a unit of time'.
http://physics.nist.gov/cuu/Units/second.html
Whether the current SI definition of a second is a fundamental physical unit could be a separate topic for this forum
The final quote in Universal.pdf is relevant, as it appears Maxwell was responding to the battle between the metric system and the English system going on at that time.
The most universal standard of length which we could assume would be the wavelength of a particular kind of light... Such a standard would be independent of any changes in the dimensions of the earth, and should be adopted by those who expect their writings to be more permanent than that body. James Clerk Maxwell, 1873
