Ancient mystic scientists achieved wonderful success in creating a new form of energy out of the combination of the thermal energy and the vital energy. This was called "yajnagni" (the oblatory fire). In order to understand it scientifically, one has to think along the following five aspects, viz, (1) reasons for the varied structures of "yajna kunda" (the pit for preserving the oblatory fire); (2) the selection of "samidhas" (wood or fuel for yajna) and their specific combustion; (3) correct pronunciation of mantras; (4) the time of yajna; and (5) the analysis of the properties of "Havan samagri" (the articles for oblation).
The heat and light that are generated by the combustion of samidhas and the Havan samagri in the kuñdas of different sizes and shapes give rise to various changes in the environment. This fact has been verified by scientific experiments. There occurs a distinct change in the intensity of heat and the quality of fire produced by the change in the samidha. For example, one can easily distinguish between the quality of fire produced by the wood of Palash (Butea Frondosa) and that produced by the wood of Kikar (Acacia).
It is a well-known fact that heat brings forth a chemical change in the material. As a result, the original property of the material also undergoes change. This is the mystery behind the production of new materials by the combustion of different materials. The Havan samagri contains two types of chemicals; namely (i) those which do not burn even in the intense heat (i.e. their effective portion is not destroyed) and (ii) those which lose their identity in the oblatory fire.
The chemical properties of materials are dependent on their physical state. The constituent components of materials in the solid state have less chance of interaction with that of the other materials. However, if the materials are transformed into a more subtle state e.g., vapor or gaseous state, the probability of interaction between the constituents of the two types of materials increases.
If we divide one cubic centimeter of matter into one thousand minute particles, their total surface area will increase ten times. But, normally, one cubic centimeter of matter has so many particles (elements or molecules) that each one of them has a diameter of the order of nanometers. Therefore its surface area will increase tremendously in the subtle state. Thus one can increase their capacity for reaction with other particles to a large extent. In this way, the particles that are unable to meet the vital air (oxygen) in the normal state, can easily meet the same in the vapor state. When metals like iron, lead etc are transformed into their subtle states at high temperatures and left in the air, they start burning with a brilliant glow and a beautiful red sparkling occurs. Sugar, coal, etc, in their subtle state, when they meet in the air, produce a crackling sound. Thus it is clear that the chemical activity of the materials can be increased by converting them into their subtle forms.