V 



THE METRIC SYSTEM. 



10 CENTIMETER RULE. 



The upper edge is in millimeters, the lower in centimeter and half centimeters. 

 UNITS. The most commonly used divisions and multiples. 



^Centimeter (cm.), i/iooth meter; millimeter (mm.), 

 i/ioooth meter; micron (/x), i/ioooth millimeter; 



LENGTH 1 the micron is the unit in Micrometry. 



I Kilometer , 1000 meters ; used in measuring roads 

 1^ and other long distances. 

 THE GRAM FOR j Milligram (mg.), i/ioooth gram. 



WEIGHT . . . ( Kilogram, 1000 grams; used for ordinary masses. 

 THE LITER FOR ( Cubic centimeter (cc.), i/ioooth liter. This is more 



CAPACITY . . I common than the correct form, milliliter. 



Divisions of the Units are indicated by the Latin prefixes : deci, 

 i/ioth ; centi, i/iooth; milli, i/ioooth. 



Multiples are designated by Greek prefixes: deka, 10 times; hecto, 

 100 times; kilo, 1000 times ; myria, 10,000 times. 



Table of Metric and English Measures. 



Meters = 100 centimeters, 1000 millimeters, 1,000,000 /*, 39.3704 inches. 

 Millimeter (mm.) = 1000 microns, i/ioth millimeter, i/ioooth meter, 



i /25th inch, approximately. 

 Micron (/x) (Unit of Measure in Micrometry) i/ioooth mm., 



i/iooooooth meter (0.000039 inch), i/25Oooth inch, approximately. 

 Inch (in.) = 25.399772mm. (25.4mm., approx.). 



Liter = 1000 milliliters or 1000 cubic centimeters, I quart (approx.). 

 Cubic centimeter (cc. or cctm.) = i/ioooth of a liter. 

 Fluid ounce (8 fluidrachms) = 29.578 cc. (30 cc., approx.). 

 Gram = 15.432 grains. 



Kilogram (kilo) = 2.204 avoirdupois pounds (2 i/5th pounds, approx.). 

 Ounce avoirdupois = (437 1/2 grains) ^ 28.349 grams. 

 Ounce troy or apothecary's = (480 grains) = 31.103 grams. 



Temperature. 



To change Centigrade to Fahrenheit: (C. x 9/5) + 32 = F. For 

 example, to find the equivalent of 10 Centigrade, C. = 10 

 (10 x 9/5) + 32 = 50 F. 



To change Fahrenheit to Centigrade : (F. 32) x 5/9 = C. For 

 example, to reduce 50 Fahrenheit to Centigrade, F. = 50, and 

 (50 32) x 5/9= 10 C.; or 40 Fahrenheit to Centigrade, 

 F. = - 40 (- 40 - 32) = - 72, whence - 72 x 5/9 = -40 C. 



(Front "T/ie Microscope" by Prof. S . H. Gage, used here with his permission.) 



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