In the end of 1860s, John Groesbeck (1833-1884), a consulting accountant from Philadelphia, Pennsylvania, and many years a teacher and principal of Crittenden’s Philadelphia Commercial College, devised a simple adding machine, for which he took out a US patent №100288 on 1 March 1870. The machine went in serial production in early 1870s, although in small quantities.
The adding device of Groesbeck was not of original construction. Similar contrivances were made earlier in 1840s in Europe by David Roth and Chaim Slonimski, there were also US patents for such devices, e.g. John Campbell (US pat. №24990) in 1859, and Thomas Strode (pat. №US30264) in 1860.
The Groesbeck’s Calculating Machine was advertised in newspapers in early 1870s (see the nearby image) and was manufactured by the company Ziegler & McCurdy, Philadelphia, and distributed by S. H. Crittenden & Co (Salmon Hodges Crittenden (1829-1864), was the brother of Samuel Worcester Crittenden (1824-1884), the founder of Crittenden’s Philadelphia Commercial College. Samuel was principal from 1844 to 1852, but then devoted himself to the work of the ministry, and from time to time afterward assisted his brother who succeeded him at the College). The device was sold for $6.00 in 1871. However, it seems the calculator was never widely sold and production was soon ceased (Ziegler & McCurdy Co. was dissolved in 1872).
The original patent had three digital positions only, but actually the machine was manufactured with more, usually five, digital positions. There are also other differences between the patented and the real-life device, e.g. the wheels in the patent are stepped (each wheel is on a different level), while in the real device all wheels are on the same level (large wheels are tilted to the left, so that successive gears are no top of the ones to the right). Also, the subtraction option is not shown in the patent.
The Groesbeck’s Calculating Machine is a row adding device, made by brass (the mechanism), nickel-plated brass (the outer casing), and steel (the pivots of the gears), with measurements: 8 cm x 16.8 cm x 7.5 cm. It has (usually) five dials and corresponding result digits, and numbers can be added into anyone of the dials.
The device hadn’t clearing mechanism (i. e. it must be cleared manually), and can be used not only for addition, but for subtraction also (the bottom row of five small windows shows the results for addition, while the top row of windows is used for subtraction). During the subtraction however, the initial number must be entered as a complement to 10.
This stylus-operated flat adding machine (usually) has five cogged and linked wheels. Each wheel has three repetitions of the integers 0 through 9; correspondingly, there are 30 teeth, for an angle of 12◦ between them. Between big wheels are placed smaller wheels, designed for performing the carry operation. The mechanism also includes detents and other advanced improvements.
The wheels are set by means of a stylus (pointer), which is placed into the concentric slots c, c’ and c” of the cap-plate in the figure 1 from the patent drawing. The result can be seen in the windows d. Actually there are two rows of result windows, one for adding and another for subtracting—five windows at the bottom show sums of numbers entered, while five result windows at the top show complementary digits and are used in subtraction.
Let’s see how the device and the inventor himself are described in the Pennsylvania School Journal, vol. 19 #7, January 1871, p. 216:
Groesbeck’s Calculating Machine.
A Practical Brain Saving Invention. Philadelphia : Ziegler & McCurdy. Price, $6.00.
Webb’s ‘Rapid Adder’ is distanced by this Quaker City invention. The inventor, Mr. Groesbeck, of the firm of S. H. Crittenden & Co., is the quiet, methodical gentleman who manages the business of their well-known Commercial College on Chestnut-st. He is also author of Crittenden’s ‘Commercial Arithmetic and Business Manual’, recently published, of which nearly a dozen editions have already been sold. He is a born mathematician—loves figures as Long Tom Coffin loved the sea—and in this machine has put into cog-wheels and pinions an idea that has long engaged his attention. The machine will do what he claims for it. We have tested it ; so have our friends ; so have our pupils. It is constructed on strictly scientific principles, and is so simple that a boy of average ability can understand and operate it. It will add with absolute certainty, taking from one to five columns of figures at a time, carrying and borrowing its own tens, hundreds, etc., without any thought or care on the part of the operator. It will also take the difference between columns with equal certainty. The machine is about six inches in length, two and a half in width, and a quarter of an inch in depth, a convenient size for use or for carrying about. It is solid metal, silver-plated, and in all respects a finished piece of mechanism.
Biography of John Groesbeck
Little is known about John Groesbeck, the inventor of this simple, but solid, reliable and perfectly working adding device.
John W. Groesbeck was born in 1833 in New York. We don’t know where he was educated (obviously he studied mathematics), but in the middle 1850s we found him in Philadelphia, Pennsylvania, where he married to the local girl Catherine Rodgers (1829–1909), the daughter of Hugh Rodgers, and Catherine McMullen. They had two daughters: Lurena Devoe Groesbeck (Wallace by marriage) (1857–1920), and Katharine Rodgers Groesbeck (Red by marriage) (1865–1900).
In 1857 John Groesbeck was hired as a teacher (Professor of book-keeping and phonography) at Crittenden’s Philadelphia Commercial College. Several years later he became the Principal of the College, and worked there for many years until his death.
Groesbeck is also known as the author of several books on commercial arithmetic, for instance The Crittenden Commercial Arithmetic and Business Manual, published for the first time in Philadelphia in 1867, and still in use (there are countless editions of this book, the last one is from 2019!)
John Groesbeck died on 7 January 1884, and was buried in Woodlands Cemetery, Philadelphia.