Muy notable la Braile.
La circular, hecha de un LP, es la MAS 346, possible por Dr. Nemeth:
"Dr. Nemeth devised a multitude of tools used by blind individuals, including a circular Braille slide rule and the internationally used standard Braille system for writing math, aptly termed the Nemeth Braille Code for Mathematics and Science Notation and the Braille slide rule which he invented with a friend at the American Foundation for the Blind, where he was working as an office clerk."
Otra pero sin photo, from a KAREN BEAUCHAMP-PRYOR letter:
"My elder sister, Christine, was already a pupil at Chorleywood. When I started she was in the sixth form and studying for her ?A? levels. I remember how lonely she was and often saw her in tears and stressed with her studies. Christine made me promise not to tell our parents, for above all she wanted the opportunity to study and do well. She succeeded in this ambition and went on to obtain exceptionally high grades, being the first blind person to achieve an ?A? level in mathematics in Europe. At that time it had been difficult for her to study mathematics as she needed a Braille slide rule, so my father John who was an engineer, designed and constructed one for her in order that she could continue with her studies."
Las instructiones y la patente que ya estan en uploads se refieren a la de Montgomery:
"Braille has been applied to various conventional devices, whereby such devices become useful to sightless U.S. Pat. No. 2,289,717. In this slide rule, a slidable position indicator permits the user to read the result of a calculation as the numeral coded in braille at the position indicated by the slide."
Y otro testimonio:
"AFB created and sold all sorts of aids and appliances in the period up to
the early 80s, and they used their record-pressing expertise to make
braille slide rules. The first model, which I have, was based on the
12-inch format and is, to me, a superior product. On one side it has dual
pointers which can be locked together or decoupled. This side has a
logarithmic scale, so it is used for multiplication and division. The
other side of the record had a linear scale and a third pointer which was
permanently locked to one on the front side. The scale on the reverse side
was linear, so you could determine base-10 logarithms of numbers by
rotating the primary pointer to a number on the front side and then read
the answer on the back.
The pointers came out almost to the circumference of the disc, where there
were various combinations of single, double and triple dots to allow you to
interpolate to better than one percent accuracy. Numbers for the scales
were embossed an inch inside the circumference, so they were covered by the
pointer. But since there were only 9 or 10 of these numbers, you could
figure out where you were by what was not covered by the large pointer.
This was one of my primary calculating tools, along with a Cranmer abacus
and some braille math tables, in going through electronics engineering
school from 1966-69 at Iowa State University.
The 10-inch version of the slide rule, necessitated by unavailability of a
12-inch record press on premises, had poorer resolution, especially for
determining logarithms, and probably disappeared from the market around
1975-77 as talking calculators began to be produced."
Bueno, esto es todo. No es que soy loco por esto asunto, es que ya he tenido papeleo con Otto van Poelje sobre las reglas braille.
Me hizo acordar a los relojes para barberías ...
Los relojes para barberías ... hace tiempo que ni se ven, pero siguen construidos:


Pelequeros saludos,
Nicolas