April 01, 2018 Sunday
Bedtime Story
Note B of Ada Lovelace - 2
We are continuing tonight with Part 2 of
Note B of Ada Lovelace.
“In the Difference Engine there are seven
of these columns placed side by side in a row, and the working mechanism
extends behind them: the general form of the whole mass of machinery is that of
a quadrangular prism (more or less approaching to the cube); the results always
appearing on that perpendicular face of the engine which contains the columns
of discs, opposite to which face a spectator may place himself.
In the analytical engine there would be
many more of these columns, probably at least two hundred.
The precise form and arrangement which the
whole mass of its mechanism will assume is not yet finally determined.
We may conveniently represent the columns
of discs on paper in a diagram like the following:-
The V’s are for the purpose of convenient
reference to any column, either in writing or in speaking, and are consequently
numbered.
The reason why the letter V is chosen for
the purpose in preference to any other letter, is because these columns are
designated (as the reader will find in proceeding with the Memoir) the
Variables, and sometimes the Variable columns, or the columns of Variables.
The origin of this appellation is, that the
values on the columns are destined to change, that is to vary, in every
conceivable manner.
But it is necessary to guard against the
natural misapprehension that the columns are only intended to receive the
values of the variables in an analytical formula, and not of the constants.
The columns are called Variables on a ground
wholly unconnected with the analytical distinction between constants and
variables.
In order to prevent the possibility of
confusion, we have, both in the translation and the notes, written Variable
with a capital letter when we use the word to signify a column of the engine,
and variable with a small letter when we mean the variable of a formula.
Similarly, Variable-cards signify any cards
that belong to a column of the engine.
To return to the explanation of the
diagram: each circle at the top is intended to contain the algebraic sign + or
-, either of which can be substituted for the other, according as the number
represented on the column below is positive or negative.
In a similar manner any other, any other
purely symbolical results of algebraical processes might be made to appear in
these circles.”
Stay tuned to the voice of an average story storytelling
chimpanzee or login at http://panarrans.blogspot.com
Good night mon ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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