[USMA:35708] A quadrant is the right angle!

[Pat Naughtin]

Title: A quadrant is the right angle!

Dear Brij and All,

I wish to comment on a point you made in your posting:
'Re: [USMA:35676] Re: decimal time'.

I have little interest in decimal time, so I won't comment on that, and I have changed the title to 'A quadrant is the right angle!'

On 16/01/06 7:06 AM, "Brij Bhushan Vij" <[EMAIL PROTECTED]> wrote:

> and 100-grad (or as I
> called Metric Degree) to arrive at Nautical Kilometre; <snip> and 90-degree quadrant AND replace Nautical Mile of 1/60th of ONE degree with *Nautical Kilometre of 1/100th of ONE Degree.

As you know from your studies of the history of the metric system, the very first unit of the metric system was the quadrant and the second unit was the metre, which was based on the quadrant.

The quadrant was needed to define the original metre as 1/10 000 000 of the distance on the Earth’s surface subtended by one quadrant. Little thought was given to the definition of the quadrant as it was assumed that everyone knew about a ‘right angle’ and how to define it.

Once the metre was defined, the quadrant quietly faded into the background of academic metrology and the quadrant has only used on a daily basis by almost everyone in the world since then. One might almost say that the quadrant (or right angle as it is also known) fits the description: ‘For all people — for all time’.

Sadly, the academic metrologists seem to be unaware of the quadrant as a practical everyday measuring unit and have tried form time to time to foist such things as radians on practical builders, which makes all corners of all rooms a ‘convenient’ π/2 radians; clearly a measurement that can be left to the junior apprentice!

I agree with you that we need to reconsider the practical measurement of angles. The International System of Units does not currently have a unit of plane angle that people can conveniently use. However, I don’t agree that resurrecting from history ‘nautical miles’, or the grads, grades, or gons of the past is the way to go.

I suggest that we simply define a quadrant as a right angle and define a new unit called a ‘quad’ equal to a quadrant.

Obviously one quadrant at the centre of the Earth would subtend a line at the surface that was (practically) 10 000 kilometres long and an angle of 1 milliquad would describe a surface distance of 10 kilometres.

This suggestion would, naturally, make the nautical mile in all its forms, such as air miles, redundant. Navigation in all forms would be much simpler as it was intended by the creators of the metric system when they chose (in 1793) to use the quadrant as the primary unit of the (then) new metric system.

Cheers,

Pat Naughtin LCAMS (USMA), Member NSAA*
PO Box 305, Belmont, 3216
Geelong, Australia
Phone 61 3 5241 2008

Pat Naughtin is the editor of the free online monthly newsletter, 'Metrication matters'.
You can subscribe by going to http://www.metricationmatters.com/newsletter

 * Pat is the editor of the 'Numbers and measurement' chapter of the Australian Government Publishing Service 'Style manual – for writers, editors and printers', he is a Lifetime Certified Advanced Metrication Specialist (LCAMS) with the United States Metric Association, a member of the National Speakers Association of Australia and the International Federation for Professional Speakers. For more information go to: http://metricationmatters.com

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