The rest of the wood was burned into gases of equivalent weight.
Explanation:
 The rest of the wood was burned into gases of equivalent weight.
-  When wood is burnt in the open air, with the help of oxygen and heat, it is transformed into carbon dioxide, water vapor, and ashes.
-  Ignition and combustion of wood mainly depend on pyrolysis which is also known as thermal combustion.
- The loss in weight of the ashes is due to the fact that gases and water vapor are also formed due to the combustion of wood.