A four beam balance is a very accurate tool for determining the weight of an object, and can even be more accurate than many digital scales. This is why it is beneficial to consider using a four beam balance if you need to obtain a precise weight.
Zero the scale by first removing any objects from the scale. Turn the adjustment knob so that the bar is pointing straight to the middle on the balance.
Add the object you choose to weigh onto the scale. Move the weights so that the bar is pointing straight to the middle once more. The measurement is reading low if the bar is angled upwards, and reading high if the bar is angled downwards.
Observe the measurements displayed on the biggest three rows. If any of the rows reads a measurement of zero, do not record that row. Observe the fourth row's measurement using proper significant figures.
Add the measurements together of all four rows to obtain the object's weight.
Use proper significant figures for the fourth row's measurement. It is acceptable to make an estimate for the last decimal place. For example, if it is larger than 0.57 but smaller than 0.58 than you may estimate the last number in the decimal.
Failure to properly calibrate the beam will result in inaccurate measurements.