Photo from Bureau of Standards 



the; standard kilogram p'rom which are de;rive;d all other weights, such 



AS THE pound troy and AVOIRDUPOIS 



The standard of mass, which is popularly called weight, is the kilogram. The one shown 

 here is made of platinum-iridium and is a copy of the original kilogram, which is preserved 

 near Paris, France. This copy is one of a number made and presented by France to the 

 different governments of the world, and is No. 4 of the series. It is always kept under the 

 double glass covers shown above, and is used onlv to check the working standards. 



in the adaptation of scientific fact to hu- 

 man need lie beyond a millionth of an 

 inch, beyond the millionth part of an 

 ounce, beyond the millionth part of a de- 

 gree of temperature. 



Just as James Watt could not make a 

 steam-engine until men were able to take 

 measurements so exact that a cylinder 

 and piston could be built which were 

 steam-tight and yet allowed free play, so 

 the perfect automobile of today had to 



wait until men could measure the five- 

 thousandth part of an inch, and the per- 

 fect ship's chronometer until he could 

 measure distance five times more minute 

 than that. As the carpenter seldom finds 

 it necessarv to consider anything less than 

 the thirty-second of an inch, and the au- 

 tomobile builder the five-thousandth of 

 an inch, each trade and profession up the 

 scale demands greater refinement, until 

 it reaches limits inconceivable to the lay- 



154 



