V 



THE METRIC SYSTEM. 







THE METER FOR 

 LENGTH 



THE GRAM FOR 

 WEIGHT . . . 



THE LITER FOR 

 CAPACITY 



OR ( 



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 (ix), i/ioooth millimeter; 

 the micron is the unit in Micrometry. 

 Kilometer, looo meters ; used in measuring roads 



and other long distances. 

 Milligram (mg.), l/ioooth gram. 

 Kilogram, 1000 grams; used for ordinary masses. 

 Cubic centimeter (cc), l/ioooth liter. This is more 

 common than the correct form, milliliter. 

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

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



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

 100 times; kilo, looo times ; myria, io,ooo times. 



Table of Metric and English Measures. 



Meters = lOO centimeters, looo millimeters, 1,000,000 /x, 39.3704 inches. 

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



I /25th inch, approximately. 

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



i/iooooooth meter (0.000039 inch), i/250oth inch, approximately. 

 Inch (in.) = 25.399772 mm. (25.4 mm., 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 = 1 5.432 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) = 3 11 03 grams. 



Temperature. 



to Fahrenheit : (C. X 9/5) + 32 = F, 



For 

 Centigrade, C. = 10° 



To change Centigrade 



example, to find the equivalent of 

 (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. 

 {From ''The Microscope,''^ by Prof. S. H. Gag-e, used here with his permission.') 



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