Stick Type Slide Rules
& Calculators etc.
By Keuffel & Esser / K & E
- Calculating Machine The idea for the Millionaire
Calculator design was first patented in 1892 by Otto Steiger of Munich Germany. Steiger's
design was later improved upon by Hans W. Egli of Zurich Switzerland. The
tag on the left side of this example has the Egli name. This example
is also marked with two US patent dates from 1895. Production of
the Millionaire Calculator began in 1893 and ended in 1935.
A total of about five thousand were manufactured. From the serial # 1633 we
can assume this example dates from just after the turn of the century. There is an online registry for these
found at John Wolff's Web Museum / Register of Millionaire Calculators. He has a number of examples listed,
(over 200) and many examples are pictured there.
The Millionaire calculator was the first
commercially successful mechanical calculator that could perform direct multiplication.
Other calculating machines of the period were adding machines that accomplished
multiplication by preforming addition calcs over and over. A much slower process. This aspect
of the design is explained in
great detail at the www.history-computer.com site. The tag on the left indicates
this example was sold here in the US. The tag reads W. A. Morschhauser
Sole Agent Madison Ave New York City. I read these machines retailed
for between $475.00 and $1100.00 at the time of manufacture. A huge sum for the time.
Note the exceptional condition. This
Antique Millionaire Calculator shows very little signs of use and
mainly just storage scuffs.
This is the less common metal case model. The Millionaire Calculator also
came in wooden cases. Overall It is in very nice condition with
typical scratches. On the interior, the areas under the swinging arms still have nearly all of the original
black finish. Many examples you can view online show considerable wear
in these areas. It is a large and heavy machine. The
measurements are approx. 7 1/4" x 25 5/8" x 11 1/4". It weighs close to 70 lbs.
the 8 column model. They could be had in larger sizes with up to 12 columns.
A rare opportunity to own a piece of calculation history. Recommended.
K & E / Keuffel & Esser 4012 Thacher Slide Rule / Calculator
(Last Model) This #4012 Thatcher calculator / slide rule is
in super nice condition. The serial # is 6285 and this # can be found
on the original OAK mounting board near the top back edge. Near the
end of production K & E stopped using the typical mahogany
mounting board and outer box and began using oak for the last few hundred
before ending production. This 4012 oak box & base variant is much harder to find than the
earlier mahogany versions. In addition to the K & E serial number
there is also a brass plaque on the base board indicating it was property of the US Navy at one
The inner scales on the drum are
white and very nice. The scales on the outer frame are near perfect as
well. They have hardly yellowed at all and there is no lifting of the
paper scales or spotting to be seen. The instructions on the base
are very nice as can be seen in the pics, . The oak box
is nice noting a few scratches and some loses to the finish. There are no names, initials,
or other carved into the box, base, or calculator.
The Thacher calculator has a near unique sliding drum design whose scales total over 30' long if laid out in a line. Edwin Thacher first patented the
idea for this slide rule / calculator in 1881 in England. The idea was an immediate success with the scientific and engineering
communities. K & E bought they rights to sell and manufacture the popular rule. Stanley initially produced them in England for K & E. and production was moved
to the states near the turn of the century. The Thatcher
calculator was first offered by K & E in their 1887 catalog as the 1740-N. In 1890 they dropped the N. In 1899 they changed the calculators
catalog # to 4012 or 4013.
The 4013 being the upgraded model w/ a built in magnifier. There were approx. 7000 total units made. The inventors name is Thacher, but it was misspelled Thatcher on almost all versions of the calculator that K & E offered,
hence the use of two different spellings of Thatcher / Thacher in this ad and on the rule itself.
A nice piece that will display well and be a great addition to the old office or calculation related collection!! Enjoy.
The Equationor or Universal Calculator Patented & Copyrighted by Walter Hart
The Equationor circular slide rule / calculator patented & copyrighted by Walter Hart is one of the rarest and most unusual
slide rules ever produced. There are no other examples, other than
this one, to be found or viewed with internet searches. There is one article by
Conrad Schure about the Hart Equationor in a 1992 issue of Oughtred Society's publication. Also the Library of Congress has a copy of the
32 page instruction booklet that anyone can download for free as a PDF. Beyond that
there are just resellers trying to market copies of the instructions that
can be had for free further down the page.
The face of the calculator has a wealth of information printed on it. In
the left top corner are the 2 copyright dates from 1888, and 1889. In the
left corner are patents from July 31 1888, and April 29 1890. The 1888
patent # is 387,070 and is titled Sliding Logarithmic Scale. It is viewable with a Google search.
The second patent from April 29th 1890 closely resembles the calculator
as it exists, right down to the sliding magnifier. That patent # is
426,444 and is titled Sliding Calculating Scale. It too comes up with
a Google search.
The simple and ingenious logo Walter Hart came up
with to market his calculating slide rule, that took 32 pages to explain how
to use, was "Arithmetic Without Figuring". Simple Genius.
The condition of this Hart Equationor is exceptional. Many circular
slide rules have a problem with the scales peeling, chipping, or otherwise
deteriorating. Not so here. There is a fine alligatoring texture
to the surface that looks to be factory and not damage. The face is
near flawless w/ one small dent chip. The magnifier is very nice.
The box is original and w/o lid. A super nice and rare piece of calculation history that will display well and be a great addition to the old office,
slide rule, or calculation related collection!! Enjoy.
& E - Keuffel & Esser 4053-3 Polyphase 7' Classroom Teaching Aid Slide Rule The
condition of this 7' teaching aid sliderule is very nice. It is
model 4053-3 Polyphase. It dates from the 1960's or 70's. I do
not think it was ever used. It was missing the cursor and I made a new
one for it. A perfectionist might not like it, but it is functional
and looks pretty good. The finish is near perfect noting that there is
a clear coat on it that is peeling in places, leaving the original paint
By Curta - Pickett - Sun Hemmi - Aristo &
N1010-ES Trig 4' Classroom Teaching Aid Slide Rule The
condition of this 4' teaching aid sliderule is very nice. It is
model # N01010-ES Trig rule. It dates from the 1960's or 70's. I do
not think it was ever used. Nice!!