is an unrealized fact that in this higher class of
life, _the law of organic growth develops into the law of
energy-growth--the mind--the time-binding energy--an increasing exponential
function of time._ That fact is of basic importance for the science and
art of Human Engineering. In mechanics we have the well-known formula

(1) Work / Time = Power.

We have seen that, in accordance with the law of geometric progression,
_PR__T_ represents the progress made--the work done--in the _Tth_ generation
(_T_ being counted from some generation taken as starting point of
reckoning); this progress, achievement, or _work_, being done in _one_
generation, we have by (1)

(2) ( Work = PRT ) / ( Time = 1) = Power,

that is, _PR__T_ = Power; this means that the number _PR__T_, which
measures the work done in a given generation, is also the measure of the
power that does the work. Now, the total work, _W_, done in the _T_
generations is

(3) _W = PR__1__ + PR__2__ + PR__3__ + ... + PR__T_;

that is,

(4) _W_ = _R_ / (_R_-1) x (_PR_T - _P_)

It should be noticed that by (2) this expression for _W_ may also be
regarded as the sum of _T_ different powers _PR_, _PR__2_, etc., each
working during one and only one generation; if we divided this sum by _T_,
the quotient would be a power that would have to act through _T_
generations to produce _W_. The reader should not fail to notice very
carefully that the expression (4) for _W_ is an expression for the total
progress made--the total work done--the total wealth produced--in the course
of _T_ generations and he should especially note how the expression
involves the exponential function of time (_T_), namely _PR__T_.

The formula makes mathematically evident the time-binding capacity
characteristic of the human class of life. Properly understood, _wealth_
consists of the fruits or products of this time-binding capacity of man.
Animals do not produce wealth; it is produced by Man and only Man. The
foregoing basic formulation should lead to further similar developments
throwing much light upon the process of civilization and serving to
eliminate "private opinion" from the conduct of human affairs. (In this
writing it is not important to look deeper into these proposed series. The
fact remains that _P_, as well as _R_, are peculiarly increasing series of
a geometrical character--the precise form will be developed in another
writing.)

Human achievements and progress, because cumula