SCIENCE OF COMMON THINGS. 21 



Avoirdupois and grain weights. English, American, and French weights. 



118 What is avoirdupois weight used for, and from whence does it 

 uerive its name ? 



Avoirdupois weight is used for the weight of mer- 

 chandise other than the precious metals. It derives its 

 name from the French avoirs (averia\ goods or chat- 

 tels, and poids, weight. 



11Q What is a grain weight f 



A grain weight is the smallest measure of weight 

 made use of in the English system. By a law of Eng- 

 land enacted in 1286, it was ordered that 32 grains 

 of wheat, well dried, should weigh a pennyweight. 

 Hence the name grain applied to this measure of 

 weight. It was afterwards ordered that a pennyweight 

 should be divided into only 24 grains. 



150 How do we make a grain weight for practical purposes f 



By weighing a thin plate of metal of uniform thick- 

 ness, and cutting out, by measurement, such a propor- 

 tion of the whole as should give one grain. In this 

 way, weights may be obtained for chemical purposes, 

 which weigh only lTr Vu1;h part of a grain. 



151 What part of an inch is a line f 



One-twelfth of an inch is designated as a line. 



1SS Are tJie standards of weights and measures in the United States 

 tlie same as in Great Britain ? 



They are essentially the same. 



1S3 Where are the standards of weights and measures to be found in 

 the United States ? 



At Washington, and at the capitals of the several 

 States of the Union ; sets having been furnished to 

 each State by the United States. 



124 Are the weights and measures used in France the same as those of 

 the United States and England ? 



No ; they are entirely different. Within a compa- 

 ratively recent time the French have reconstructed 

 their old system of weights and measures, and formed 

 another on an entirely new plan. The French system 

 is, at present, the best and most accurate system 

 existing. 



