Advocacy Research: The Lesson of the Chronometer

Fredric K. Schroeder, Ph.D.

Preferred Citation

Schroeder, F. K. (2010). Advocacy research: The lesson of the chronometer. Journal of Blindness Innovation and Research, 1(1). Retrieved from doi:


What does the British Longitude Act of 1714 have to do with the literacy of blind children? Ship's navigation requires a means of measuring latitude (the angular distance north or south of the equator, measured in degrees along a meridian, as on a map or globe) and longitude (the angular distance on the earth or on a globe or map, east or west of the prime meridian at Greenwich, England, to the point on the earth's surface for which the longitude is being ascertained, expressed either in degrees or in hours, minutes, and seconds). Determining latitude is relatively easy in that it can be calculated from the altitude of the sun at noon with the aid of a table giving the sun's declination for the day (the sun's variance from the celestial equator measured in degrees).

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