Remove both coins, zero the balance, and weigh both coins together, recording the total mass. If you have no
TARE bar on your balance, add the second coin and measure and record the mass of the two coins. Then
remove both coins and find the mass of the second one by itself. When you are satisfied that your results are
those you would expect, go to the stockroom and obtain a glass-stoppered flask, which will serve as a pycnometer, and samples of an unknown liquid and an unknown metal.