SCIENCE, INVENTION, DISCOVERY. 



335 



comes near them, we have a grand display of 

 celestial fireworks. 



It ie estimated that the average number of 

 meteors that traverse the atmosphere daily, 

 and which are large enough to be visible to 

 the eye on a dark, clear night, is 7,500,000 ; 

 and if to these the telescopic meteors be added, 

 the number will be increased to 400,000,000. 

 In the space traversed by the earth there are, 

 on the average, in each volume the size of our 

 globe (including its atmosphere), as many as 

 13,000 small bodies, each one capable of fur- 

 nishing a shooting star visible under favorable 

 circumstances to the naked eye. 



Metric System, The, originated in France 

 about 1790. In 1799, on the invitation of 

 the Government, an international convention, 

 at which were present representatives from 

 France, Holland. Denmark, Sweden, Switzer- 

 land, Spain, Savoy, and the Roman Republics, 



assembled at Paris to settle, from the results 

 of the great Meridian Survey, the exact length 

 of the " definitive meter." As a result of the 

 investigations of this learned body, the Metric 

 System was based upon the length of the fourth 

 part of a terrestrial meridian. The ten-mil- 

 lionth part of this arc was chosen as the unit 

 of measures of length, and called Meter. The 

 cube of the tenth part of the meter was adopted 

 as the unit of capacity, and denominated Liter. 

 The weight of a liter of distilled water at its 

 greatest density was called Kilogramme, of 

 which the thousandth part, or Gramme, was 

 adopted as the unit of weight. The multiples 

 of these, proceeding in decimal progression, are 

 distinguished by the employment of the pre- 

 fixes deca, hecto, kilo, and myria (ten, hundred, 

 thousand, ten thousand) from the Greek, and 

 the subdivisions \)jdeci, centi, and milli (tenth, 

 hundredth, thousandth) from the Latin. 



Measures of Length (Unit, Meter). 



Cubic Measures, or Measures of Capacity (Unit, Uter). 



EQUAL TO Cubic Inches. 



Milliliter, or cubic centimeter 0.06103 



Centiliter, 10 cubic centimeters 0.61027 



Deciliter, 100 cubic centimeters 6.10271 



LITEK, or cubic Decimeter, 61.02765 



Decaliter, or Centistere 610.27052 



Hectoliter, or Decistere 6,102.70515 



Kiloliter, or Stere, or cubic meter, 61,027.05152 



Myrialiter, or Decastere 610,270.51519 



Cubic Feet. 



0.000035 



0.000353 



0.003532 



0.035317 



0.353166 



3.531658 



35.316581 



353.165807 



Pints. 



0.00176 



0.01761 



0.17608 



1.7C077 



17.60773 



176.07734 



1,760.77341 



17,607.73414 



Measures of "Weight (Unit, Gramme). 



EQUAL TO Grains. Troy Oz. 



Milligramme 0.01543 0.000032 



Centigramme 0.16432 0.000322 



Decigramme 1.54323 0.003215 



GRAMME 1543235 0.032151 



Decagramme 154.32349 0.321507 



Hectogramme 1,543.23488 3.215073 



Kilogramme 15,432.34880 .. 32.150727 



Myriagramme 154,323.48800 .. 321.507267 



(roirdupois Lbs 

 0.0000022 

 0.0000220 

 0.0002205 

 0.0022046 

 0.0220462 

 0.2204621 

 2.2046213 

 22.0462129 



Gallons. 



0.0002201 



0.0022010 



0.022005,7 



0.22001:67 



2.2009668 



22.0096677 



220.0966767 



2,200.9667675 



Cirt. of 112 Lbs 

 0.0000000 

 0.0000002 

 0.0000020 

 0000197 

 0.0001968 

 0.0019684 

 0.0196841 

 0.1968412 



Square Measures, or Measures of Surface (Unit, Are). 



EQUAL TO Sq. Feet. Sq. Yards. Sq. Perches. Sq. Hoods. 



Centare, or square meter 10.794299 .. 1.196033 .. 0.0395383 .. 0.0009885 



ARE, or 100 square meters 1,076.429934 .. 119.603326 .. 3.9538290 .. 0.0988457 



Hectare, or 10,000 square meters... 107,642.993419 ..11,960.332602 .. 395.3828959 .. 9.8845724 



Miles. 



0.0000006 

 0.0000062 

 0.0000621 

 0.0006214 

 0.0062138 

 0.0621381 

 0.6213824 

 6.2138242 



Rushels. 



0.0000275 



0.0002751 



0.0027512 



0.0275121 



0.2751208 



2.7612085 



27.5120846 



275.1208459 



Tons. 



n.ooooooo 



0.0000000 

 0.0000001 

 0.0000010 

 0.0000098 

 0.0000984 

 0.0009842 

 0.0098421 



Sq. Acres. 

 0.0002471 

 0.0247111 

 2.4711434 



Microphone, The, is the black carbon 

 button used in telephones, and is an instru- 

 ment for magnifying sound. The most sensi- 

 tive substance, so far as yet discovered, to have 

 the peculiar power, when placed in the electric 

 current, of magnifying sound, is willow char- 

 coal plunged, when at white heat, into mercury. 

 A piece of such charcoal an inch long, placed 

 vertically between two blocks of carbon, hol- 

 lowed to receive its ends, wires connecting the 

 blocks with an electric battery, and the ordi- 

 nary receiving instrument of a telephone, con- 



stitute one of the simplest forms of a micro- 

 phone. The invention of the microphone is 

 claimed by Professor Hughes of England, and 

 Thomas Edison, the American inventor. 



Microscope, Invention of the. It is 

 generally believed that the first compound mi- 

 croscope was made in 1590 by a Hollander 

 named Zacharias Jansen. Pocket microscopes 

 were first made in London in 1740 by Ben- 

 jamin Martin. The discovery of the magnify- 

 ing power of the simple lens was undoubtedly 

 made long before the Christian era, as it is 



