60 



GREEN S STANDARD BAROMETER. 



If, as in Fig. 5, we find the line of the vernier coinciding with 

 the third line of the tenths above 29, we read 29.300. 



If, as in Fig. 6, on this page, we find the index at 29 inches 

 3 tenths and 5 hundredths, we read 29.350. 



If, as in Fig. T, we find the index at 30 inches no tenths 5 

 hundredths and something more, this additional quantity we 



Fig. 6. 



Fig. 7. 



shall find by looking up the vernier scale, until we come to some 

 one line on it, coinciding with a line on the other scale. In this 

 instance it is the line marked 2, and indicates 2 hundredths, to 

 be added to the other numbers, making 30.010. 



If, as in Fig. 8, we find 29 inches no tenths 5 hundredths, and 

 on the vernier the second line above that marked 2, is found to 

 coincide with the scale, each of these short lines indicates 2 



