Bardon proceeds with an introductory study of the elements, beginning with the tattwas. He does not go into depth on the tattwas, except that they may be valuable in their timing for works with particular elements. The tattwas, like astrological planetary hours, have periods of time beginning with sunrise to sunset, each element with its own assigned time in progression and repeated cycle.
The tattwas system is also valuable to the magician in its symbolism, as it represents further subdivisions of the elements in a continued numerical and elemental fashion. Anyone familiar with tattwas care to comment? I recommend further study.

akasha-spirit
tejas-fire
apas-water
waju-air
prithivi-earth

One of the things I like best about Bardon's analysis of the elements is his emphasis on the polarity and duality each element has.
A positive and negative aspect, not to be confused with good and evil, but pointing to the constructive and destructive aspects.
He continually uses this interpretation interchangably with 'electric and magnetic' fluids, indicating something more akin to an 'astral charge'. As we progress we will see how this becomes his tetrapolar magnet, and his key to understanding the elements and all that is. He begins then with FIRE, although it is explained that ETHER or AKASHA is the source from which all the elements originate, yet he does not say whether akasha is considered an element itself. I would suspect that he would not, judging from his further definitions and views. He does point out that AIR and EARTH are not elements proper, to the initiate. I think this is a moot point and only serves to confuse. I will explain momentarily.