PROJECTS 605 



Caution. Notice that when a hand is between two figures, the 

 lesser is read, just as in the case of the hour-hand of a clock. If the 

 hand is very near a figure, and you do not know whether it is just 

 short of the figure or just past the figure, the following circle will 

 guide you. For example a careless observer might read the 2d 

 circle 2000. If it were 2000, then the hand in the 3d circle would 

 have reached or passed it. Since the hand in the 3d circle has not 

 quite reached 0, the 2d dial-hand is to be read 1000 instead of 

 2000. In other words, think of the dial hand which shows a doubt- 

 ful reading as the hour-hand of a clock, and the dial-hand of the 

 following circle as the minute-hand. If the "minute-hand" has 

 completed a revolution and points to or beyond, read the figure 

 toward which the " hour-hand" is pointing. If the " minute-hand " 

 has not quite reached 0, read the lesser figure preceding the "hour- 

 hand." 



It can be seen that a quick way to read the dial is to begin with 

 the 10 circle and put the figures down in reverse order. Thus, the 

 10 circle records units, the 100 circle tens, the 1000 circle hundreds, 

 etc. 



Commercially, one cubic foot is equal to 7 gallons, and so if you 

 wish to reduce cubic feet to gallons, multiply by 7. 



The dial cannot be set back to after reading. The record 

 is continuous. To ascertain the amount of water used in June, 

 for example, you would have to subtract the reading taken on the 

 31st of May from the reading taken on the 30th of June. You can 

 also ascertain the amount of water used for any single purpose, 

 such as sprinkling the lawn, by taking the readings before and after 

 using the water. 



If you suspect that water is being wasted through some leak, 

 close all outlets tight, and observe the circle on the dial marked 

 "one foot." If it continues to move, there is a leak somewhere 

 on your premises, since the meter can register only when water is 

 passing through it. 



A gas-meter does not record any number of cubic feet smaller than 

 hundreds. Consequently, the last two circles on a water-meter, 

 recording tens and units, are missing on a gas-meter. 



