150 



GENERAL SCIENCE 



the other mechanism by means of the shaft (102) and the gear 

 wheel (103). 



Gas Meter Index and How to Read It. Gas meters are provided 

 with an index. The top dial of the index is called the test dial. One 

 revolution of the test hand indicates that 2 cubic feet of gas have 

 passed through the meter. 



Of the large dials the first one at the right is usually marked 



FIG. 116. 



" 1 thousand. " This means that during one revolution of the hand 

 1000 cubic feet of gas have passed through the meter. The dial is 

 divided into ten equal parts so that the passage of the hand over 

 each part indicates the passage of T ^ of 1000 cubic feet, or 100 cubic 

 feet. 



If the first dial is marked 1 hundred, the second dial will be 

 marked 1 thousand, the third 10 thousand and the fourth 100 

 thousand, etc. 



