Even induced magnetic currents, the cheapest known form of electric energy, can be obtained only by the use of steam power.

You generate steam by the combustion of coal: electricity, without steam, can only be generated by the combustion of metals.

Coal is much cheaper than metal: consider the vast amount of coal consumed in smelting metals.

Still, electricity is a much greater force than steam: it's stronger, so to speak.

Sixpennorth of electricity would do more work than sixpennorth of steam if only you could catch it and hold it without waste.