But steamships didn't lose their sails until the 1880s, because early marine engines had a nasty habit of breaking down.

Until ships became large enough (and engines small enough) to mount two engines side by side, they needed to keep sails.

Modern airplanes have two black boxes: a voice recorder, which tracks pilots' conversations,and a flight-data recorder, which monitors fuel levels, engine noises and other operating functions that help investigators reconstruct the aircraft's final moments.

It's clear that petrol-driven engines have no future.

Now, however, recent developments in electric vehicle technology mean they can match conventional petrol engines in terms of performance and safety

He quotes Google co-founder Larry Page to the effect that the perfect search engine will understand exactly what I mean and give me back exactly what I want.

Some of the heat is used directly or produces useful work; the rest is lost or rejected, radiated into the atmosphere from the engines, motors, boilers and all the energy-consuming machinery that makes American’s wheel go around.

His main thesis is that the buzz of urban life, and the opportunities it offers for co-operation and collaboration, is what attracts people to the city, which in turn makes cities into the engines of art, commerce, science and progress.

Google's core business is search and find, so obviously what helps improve Google's search engine is good for Google," he says.

make full use of the power of its search engine

Lending is the coal to our engine, so we want to make more loans.

The partnership benefits both sides by allowing unconventional partners for example, two companies from two different industries to work together on a specific aspect of the value chain, like, in this example, an engine firm with an accessory one.