IV : 
THE METRIC SYSTEM. 
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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.), 1/tooth meter; mdl/imeter (mm.), 
metre RRR HOR ai rae 3 micron (4), 1/toooth millimeter ; 
TeNGTT . . the micron is the unit in Micrometry. 
Kilometer, 1000 meters; used in measuring roads 
and other long distances. 
THE GRAM FOR § AGilligram (mg.), 1/toooth gram. 
WEIGHT . j Kilogram, tooo grams; used for ordinary masses. 
THE LITER FOR ; Cubic centimeter (cc.), 1/toooth liter. This is more 
CAPACITY common than the correct form, milliliter. 
‘ Divisions of the Units are indicated by the Latin prefixes: deci, 
1/toth; centi, 1/1ooth; mz//z, 1/1oooth. 
Multiples are designated by Greek prefixes: deka, 10 times; hecto, 
100 times; 42/0, 1000 times ; myria, 10,000 times. 
Table of Metric and English Measures. 
Meters = 100 centimeters, 1000 millimeters, 1,000,000 mu, 39.3704 inches. 
Millimeter (mm.) = 1000 microns, 1/1toth millimeter, 1/1oooth meter, 
1/25th inch, approximately. 
Micron («) (Unit of Measure in Micrometry)' = 1/1oooth mm., 
1/toooocoth meter (0.000039 inch), 1/25000th inch, Bp prasinately: 
Inch (in.) = 25.399772 mm. (25.4mm., approx.). 
Liter = 1coo milliliters or 1000 cubic centimeters, 1 quart (approx.). 
. Cubic centimeter (cc. or cctm.) = 1/roooth of a liter. 
_ Fluid ounce (8 fluidrachms) = 29.578 cc. (30 cc., approx.). 
'. Gram = 15.432 grains. 
_ Kilogram (kilo) = 2.204 avoirdupois pounds (2 1/5th 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 Geutlessea, F. = 50°, and 
(50° - 32°) x 5/9 =10° C.; or — 40 Fahrenheit to Centigrade, 
= — 40° (— 40° — 32°) = — 72°, whence — 72° x 5/9 = —40°C. 
id “The Microscope,” by Prof. S. H. Gage, used here with his permission.) 
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