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Dataset from Michelson's speed of light measurements in 1879.




Speed of Light

NPM version Build Status Coverage Status Dependencies

Dataset from Michelson's speed of light measurements in 1879.


$ npm install datasets-michelson-speed-of-light

For use in the browser, use browserify.


var data = require( 'datasets-michelson-speed-of-light' );


Dataset from Albert Michelson's speed of light measurements made from June 5 to July 2, 1879. The dataset comprises 5 experiments, each having 20 runs, thus yielding 100 measurements. Measurement values are in units of millions of meters per second.

console.log( data );
		[299.85, 299.74, 299.9, ...],
		[299.96, 299.94, 299.96, ...],
		[299.88, 299.88, 299.88, ...],
		[299.89, 299.81, 299.81, ...],
		[299.89, 299.84, 299.78, ...]


var toMatrix = require( 'compute-to-matrix' ),
	mean = require( 'compute-mean' ),
	variance = require( 'compute-variance' ),
	data = require( 'datasets-michelson-speed-of-light' );

var mat,

// Convert the data into a matrix:
mat = toMatrix( data );
    [ 299.85  299.74  299.9  ...
        .    .           .
        .       .        .
        .          .     .
      299.89  299.84  299.78 ... ]

// Calculate the sample mean across the rows (experiments):
mu = mean( mat );
    [ mu_1
      mu_5 ]

// Calculate the sample variance across the rows:
s2 = variance( mat );
    [ s2_1
      s2_5 ]

// Calculate the mean across all experiments:
console.log( mean( mu ) );
// returns 299.8524 => true value is 299,792,458 m/s

To run the example code from the top-level application directory,

$ node ./examples/index.js


  • Michelson, Albert A. (1882). "Experimental determination of the velocity of light made at the United States Naval Academy, Annapolis." Astronomic Papers 1 135–8. U.S. Nautical Almanac Office. (See Table 24.)
  • Dorsey, Ernest N. (1944). "The Velocity of Light." Transactions of the American Philosophical Society, Volume 34, Part 1, Pages 1-110, Table 22.



Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov


MIT license.


Copyright © 2015. The Authors.