The apparatus shown in the diagram can be used to investigate the temperature rise produced in a known volume of water when a sample of methanol is burned in a spirit burner.

A student carries out the first few steps of the method:
Describe the remaining steps of the experimental procedure required to find the mass of methanol consumed to raise the temperature of the water by exactly 30 ∘C30\text{ }^{\circ}\text{C}30 ∘C.