12 CHEMISTRY FOR AGRICULTURAL STUDENTS 



As the names imply, it will be found that — 



I decigram = .i gram. i dekagram = lo grams. 



I centigram = .01 gram. i hectogram =100 grams. 



I milligram = .001 gram. i kilogram = 1000 grams. 

 The relations between this — the metric — and the avoirdupois 

 systems are the following : — i gram = 15.432 grains; i ounce 

 = 28.35 grams; i kilogram = 2.2 lbs. 



The metric standard of length is the meter, the parts an4 

 multiples of which are similar to those of a gram. Examine 

 a meter measure and note that — 



I decimeter = .1 meter. i dekameter =10 meters. 



I centimeter = .01 meter. i hectometer = 100 meters. 



I millimeter = .001 meter, i kilometer = 1000 meters. 

 Of the relations between the metric and the British systems, 

 I meter = 39.37 inches, i inch = 2.54 centimeters, i mile = 

 1.6 kilometers. 



The standard of capacity is the liter. Examine a cube 

 having a volume of 1 liter, and note that it is the measure of 

 I cubic decimeter or 1000 cubic centimeters. Hence — 

 .001 liter = I cubic centimeter. 

 1 liter = I cubic decimeter. 

 1000 liters = I cubic meter. 

 Quantities measuring less than a liter are usually spoken of as 

 so many cubic centimeters (" cc"). Of the relations between 

 the metric and British systems, i liter = 1.76 pints and i 

 pint = 567 cc. 



A cubic centimeter of pure water measured at 4" C. weighs i 

 gram. This simple relation between volume and weight pro- 

 vides a means of correcting. the graduation of glass measures, 

 these being often unreliable. Calibrate a 20 cc. measure as 

 follows -.—Having cleaned and dried the measure, first weigh 

 it empty. Then fill it with pure water from a wash bottle to 

 the 10 cc mark and weigh again. Now fill it to the 20 cc 

 mark and weigh a third time. Subtract the weight of the 

 measure from the weight of the measure and water, in order 



