There will result the second curve of losses, R, R, R, intersecting the
second curve of gains at the point F, the new economic point for our new
conditions.

These two examples fully illustrate the whole subject, furnishing an easy
and, when carefully made, a very exact calculation and result.

The following are a few of the general conclusions to be drawn:

1. That radiation is a tangible and measurable cause, sufficient to
account for all losses heretofore ascribed to an intangible,
immeasurable, and wholly imaginary cause, viz., "internal evaporation and
re-evaporation."

2. In order to prevent the high initial temperatures now used becoming a
source of loss, it is necessary to prevent the quantity dS (t'-t)
becoming great, by making dS as small as possible. In other words, we
must compound our engines. Thus for the first time is pointed out the
true reason why compound engines are economical heat engines.

3. The foregoing reasoning being correct, it follows that steam jackets
are a delusion.

4. In order to attain economy, we must have high initial temperatures,
small high pressure cylinders, low back pressures from whatsoever cause,
high piston speeds, short rather than long strokes, to avoid the cooling
effects of a long piston rod; but especially must we have scrupulous and
perfect protection from radiation, especially about the cylinder heads,
now oftentimes left bare.