Read the dials from right to left and ensure that the covering glass is clean for clear reading. Read the dials in the direction indicated by the arrow marked on the dial. If not marked with the arrow, identify and read in the direction of rotation of the pointer.
Read the first right-most dial and note the number indicated by the pointing dial-hand. If the pointer is in between two numbers, read the lower number.
Read the second dial -- to immediate right of the first dial. If the pointer is between two numbers, read the lower number. If the pointer is exactly at a number, observe the dial on the immediate right.
Read the next dial in the same manner and note the corresponding readings.
Write the corresponding numbers noted from the dials in the in the same sequence, right to left. The reading obtained is the total volume of gas that has passed through the meter.
Subtract the previously recorded reading from this reading, to get the latest reading.