The ingredients of line and column actions in the Peninsula, according to Oman are:
“(1). The line must not be exposed before the moment of actual conflict: i.e. it must be kept under cover as much as possible.
(2). That till the critical moment it must be screened by a line of skirmishers impenetrable to the enemy’s tirailleurs.
(3). That it must be properly covered on its flanks, either by the nature of the ground, or by cavalry and artillery.”.
Oman goes on to expand on these factors and points out that by keeping the line under cover protected it from the physical and psychological effects of artillery fire.
Oman then goes on to conclude his chapter on infantry tactics in the Peninsula with the much repeated description of a typical French attack by General Bugeaud which describes a British volley followed by a bayonet charge.
This says Oman “is the picture that we need to complete our study of the conflict of column with line.”.
Oman really didn't say it was just firepower but the more effective your fire the better.