This is a volume on material science authored by Pandit Madhusudan Ojha. This is a Hindi translation. According to him, there are three kinds of material in the world—substance, liquid and vapor. The element whose atoms stick together fall in the substance category. The elements which are liquid in nature fall in the second category. The elements whose atoms remain scattered are vapor material like air and blinding light. These elements have `bala` (force) within them.