# Eri Jewett

In the late 1880s Eri Ferris Jewett (1835-1916), a civil engineer and surveyor from Newtown, Hamilton County, Ohio, invented a simple calculating device, one of the many incarnations of Abaque Rhabdologique of Claude Perrault. In April 1890 Jewett applied for a patent, which was granted on 17 February 1891 (US patent No. 446753), as the patent was assigned to Jewett’s second son—Dr. Percy Livingston Jewett.

The calculating device of Jewett is described in the 1898 book THE ARITHMACHINIST. A Practical Self Instructor in Mechanical Arithmetic. of Henry Goldman thus:
More complex in its arrangement, but hardly better in its workings, is Jewett’s Calculator, having seven tape-bands with figures printed thereon, which show through the small openings at the head of the device and indicate the result. Circular holes and a pencil are employed for moving the tape bands and number scales serve as guides. The outer case is of aluminum and about one inch deep. The carrying of tens is accomplished by a mental process, which sacrifices the most important advantage to be derived from the adoption of a computing machine.

Let’s examine the operation of Jewett’s Calculator, using the patent drawing (see the nearby image):
The machine is operated as follows: If the machine is to be used for adding, a pointed instrument-such, for instance, as a lead pencil-is inserted in the perforation (marked on the drawing with h), and the card J is moved to bring the numerals opposite the holes g in the bars H’ in such a manner that they will read from bottom to top, and the tapes E are turned by inserting the pencil in the perforations e’, so that a row of ciphers will appear in the slot F. We will suppose that the three numbers 223, 179, and 845 are to be added. Beginning with the figure in the units-column of the last number 5 the operator places his pencil in a perforation e’ of the tape E opposite the numeral 5, as displayed in the right-hand or units column on the machine, and moves the pencil and tape to the bottom of the slot f. This causes the numeral 5 to appear in the units-column of slot F. The pencil is then placed in a perforation of the tape opposite the numeral 9, that being the next numeral to be added, and the tape drawn to the bottom of the slot f, as before, and this causes the numeral 4 to appear in the units-column of the slot F; but the right-hand pulley will have completed a revolution during this last movement and the pin C will have struck a tongued, warning the operator that there is one to carry. The pencil is therefore inserted in a perforation of the tape opposite the Fig. 1 in the tens-column and the tape and pencil are moved to the bottom of the slot f, and this causes the numeral 1 to appear in the tens-column of the slot F. The operator then inserts the pencil opposite the numeral 3 in the units-column of the machine, and the tape and pencil are again carried to the bottom of the slot f, thus causing numeral 7 to appear in the units column of the slot F. The numerals 4, 7, and 2 being the numerals in the tens-column of the numbers to be added, are then added in the tens-column of the machine in the manner described, the amount to carry transferred to the hundreds-column of the machine, and the hundreds are added in the same way, and the final result 1,247 will appear in the slot F. It will be readily seen that as each tape and set of pulleys are independent of the others the operation may be carried on indefinitely, being only limited by the number of tapes and corresponding parts in the machine.
To subtract, the above process is reversed, the card J is moved upwardly so that the numerals in the holes g will read from top to bottom, and instead of the row of ciphers in the slot F the minuend is made to appear in the right-hand side of the slot. The operator then places his pencil in the perforations of the tapes opposite the numerals of the units, tens, &c., corresponding to the numerals in similar columns of the subtrahend, and moves the tapes upwardly, carrying as in addition, but upwardly, and the remainder appears in the slot F.

#### Biography of Eri Jewett

Eri Ferris Jewett was born on 5 March 1835 in Red Bank, Hamilton, Ohio, USA. He was the son of Dr. Eri Leonard Jewett (1803-1854) and his wife Sarah Knapp (Ferris) Jewett (1814–1840).

Dr. Eri Leonard Jewett was born on 9 April 1803, in Vermont, USA, and was only several years old when removed together with his parents to Ohio. He graduated from the Miami Medical College of Cincinnati and practiced there for quite a few years. In 1832 he married in Red Bank, Ohio, to the young Sarah Knapp Ferris, daughter of Joseph Ferris (1776-1831) and Priscilla Knapp Ferris (1793-1872) from Greenwich, Connecticut. They had only one child, our hero Eri Ferris, before the early death of Sara (she was only 25) on 7 March 1840. In the middle 1840s, Doctor’s health also worsened. He traveled for three years to Texas after the Mexican War, with the object of regaining his health, but his ailment eventually developed into consumption, and he died in College Hill, Ohio, in 1854, appointing his mother-in-law, Priscilla Ferris, in his will, as guardian for his son.

After studying civil engineering in the late 1850s Eri Ferris entered the army and was a soldier in the Civil War, serving first as aide-de-camp to General Rousseau, in Grant’s Army during the Tennessee Campaign, and later as Lieutenant-Colonel of the 138th Ohio Infantry.

Leaving the army at the beginning of 1864, Eri Ferris Jewett married in Newtown, Ohio, on 13 May 1864, Lida P. Brown (1837-1890), who was born in Newtown on 8 Jan. 1837, daughter of Dr. Thomas Mercer Brown (1806-1886) and Selina M. (Williams) Brown (1810-1879). They had four sons and one daughter: John Brown (1865–1939, he became a writer), Percy Livingston (1867–1905, he became a physician and surgeon), William Frederick (1870–1937), Arthur Eri (1873–1913), and Madge Ruth (b. 9 Nov. 1875).

After 1864 Eri Jewett lived in Newtown, Ohio, and upon working several years as a civil engineer, he was appointed Deputy County Surveyor of Hamilton County, Ohio, from 1870 to 1873, and then became County Engineer of the same county from 1879 to 1884. Besides the above-mentioned patent for adding machine, Eri Ferris Jewett was a holder of another US patent for Controllable Power-Transmitting Mechanism (US patent No. 894010 from 31 July 1908), assigned to his eldest son John Brown.

Eri Ferris Jewett died on 13 March 1916 (aged 81) of bronchial asthma and apoplexy in Newtown, Ohio.