THE ENERGY OF THE SUN, AND HOW HEAT IS MEASURED
In the first chapter we tried to give a clear view of the prime factors necessary to develop motion. The boy must thoroughly understand the principles involved, before his mind can fully grasp the ideas essential in the undertaking.
While the steam engine has been the prime motor for moving machinery, it is far from being efficient, owing to the loss of two-thirds of the energy of the fuel in the various steps from the coal pile to the turning machinery.
First, the fuel is imperfectly consumed, the amount of air admitted to the burning mass being inadequate to produce perfect combustion.
Second, the mechanical device, known as the boiler, is not so constructed that the water is able to completely absorb the heat of the fuel.
Third, the engine is not able to continuously utilize the expansive force of the steam at every point in the revolution of the crankshaft.
Fourth, radiation, the dissipation of heat, and condensation, are always at work, and thus detract from the efficiency of the engine.
The gasoline motor, the next prime motor of importance, is still less efficient in point of fuel economy, since less than one-third of the fuel is actually represented in the mechanism which it turns.
The production of energy, in both cases, involves the construction of a multiplicity of devices and accessories, many of them difficult to make and hard to understand.