THE METRIC SYSTEM. 



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

 centimeters. 



Units. The most commonly uskd divisions and multiples. 



' Centimeter (cm), i/ioo meter; Millimeter (mm), 

 _ M . i/iooo meter; Micron (//), i/iooo millimeter. The 



1 HE METER, tor I micron ; s the unit m micrometry. 



length Kilometer, ioo meters; used in measuring roads and other 



long distances. 

 T „ f ( Milligram (rag), i/iooo gram. 



1HE L.RAM, tor ) KH os r ranl IO oo grams, used for ordinary masses, like 



WEIGHT ( groceries, etc. 



The Liter, for ( Cubic Centimeter (cc), i/iooo liter. This is more 



capacity .... , ( common than the correct form, Milliliter. 



Divisions of the units are indicated by Latin prefixes: deci, i/io; centi, 

 i/ioo; milti, i/iooo. 



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

 times; kilo, iooo times; myria, 10,000 times. 



TABLE OF METRIC AND ENGLISH MEASURES. 



Meter = 100 centimeters, 1000 millimeters, 1,000,000 microns, 39.3704 

 inches. 



Millimeter (mm) = 1000 microns, 1/10 millimeter, 1/1000 meter, 1/25 inch, 

 approximately. 



Micron (/j) (unit of measure in micrometry) = 1/1000 mm, i/ioooooo me- 

 ter (0.000039 inch), 1/25000 inch, approximately. 



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



Liter = 1000 milliliters or 1000 cubic centimeters, 1 quart (approx.). 



Cubic centimeter (cc or cctm) = 1/1000 liter. 



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



Gram = 15.432 grains. 



Kilogram (kilo) = 2.204 avoirdupois pounds (2\ pounds, approx.). 



Ounce Avoirdupois (437^ grains) = 28.349 grams ^(30 grams, 



Ounce Troy or Apothecaries' (480 grains) = 3 1 . 103 grams j approx. ). 



TEMPERATURE. 



To change Centigrade to Fahrenheit: (C. X |) + 32 = F. For example, to 

 find the equivalent of 10° Centigrade, C. = io°, (lo° Xf)+3 2 = 5°° F - 



To change Fahrenheit to Centigrade: (F. — 32°) Xf = C For example.to 

 reduce 50° Fahrenheit to Centigrade, F. = 50°, and(50°— 32°) X f = 10° C. ; 

 or — 40° Fahrenheit to Centigrade, F. = —40°, (— 40 — 32°) = — 72°, 

 whence — 72 X|-=- 4°° C. 



— From '■'■The Microscope" (by S. & Gage) by permission. 



