56 Domestic Science 



raised, and a reading of the pointer indications made 

 while the balance is thus protected from the effects 

 of accidental currents of air. Should this second 

 reading show that the weight has been obtained as 

 nearly as can be effected with the balance and weights 

 used, add up the weights on the pan, note the total 

 and then replace them in order in their proper com- 

 partments in the box, checking the total weight found 

 while so doing. Close the front of the balance and the 

 lid of the box when the weighing is finished. 



EXPERIMENT 15. Place a 1 oz. weight on the left- 

 hand pan of the balance and find its weight in grams 

 by the method of the previous experiment. From the 

 result find by calculation the weight of 1 kilogram in 

 pounds and compare your value with that shown under 

 the table of Metric weights previously given. 



The balance may be used to determine indirectly 

 the areas of irregular or curvilinear figures such as 

 those of which the areas have been found by other 

 methods in previous experiments, or to check the results 

 obtained for regular figures by calculation from their 

 dimensions. 



EXPERIMENT 16. Obtain some tough millboard of 

 medium thickness and of good quality, or some thin 

 sheet zinc. Cut carefully from one of these media a 

 square of definite area, say 4 sq. in. or 25 sq. cm. 

 Weigh this as accurately as possible and from the result 

 determine the weight of 1 sq. inch or 1 sq. cm. of the 

 material used. Trace the outline of an irregular figure, 

 of which the area is to be found, on the millboard or 

 zinc. Cut out the figure as neatly as you can and 

 weigh it. Assuming that the weights of the figures 

 are proportional to their areas, the area of the figure 



