8.21 America’s Earliest Part II

According to Florian Cajori in his 1909 treatise,77 the earliest slide rule made and distributed in America appeared to be the circular slide rule of Palmer, c. 1843, which is described in the vignette America’s Earliest Slide Rule. As we know, Keuffel and Esser began their slide rule manufacturing in the U.S. in the mid-1890s, followed by the likes of Dietzgen and Richardson in the early 1900s, Gilson by the mid-1910s, and on it went. So it seemed easy to accept that the Palmer’s scale, for sale over 50 years earlier, was likely the first. Or was it?

Even Cajori left open the possibility that there could have been earlier American-made slide rules, claiming that the Palmer scale was “one of the first, if not the first, slide rule” made in the U.S.78 So what, if any, slide rules – Carpenter’s rules, for instance – were perhaps being made earlier in America? In an interesting article found in the Journal of the Oughtred Society,79 Thomas Wyman discusses the early Gunter’s rules, Carpenter’s rules, and Engineer’s rules that were being made in the early part of U.S. history. A number of boxwood rule makers were formed, mostly in Connecticut, in the mid-1800s. The famous Stanley Rule & Level Company is a good example. And Wyman discusses a Carpenter’s rule that was made by Clark & Co., of Vermont, c. 1835 or so. But, as he points out, the earliest known company of this kind was formed in 1821, by Thomas Belcher of New York. And the Belcher company was known to have made Gunter’s rules and other rules with Gunter scales.

8.21.1 An Early Belcher Slide Rule

The Oughtred Society lists its “Rarities” in which a couple of Gunter scales are shown that were made by Belcher Brothers & Co. A cursory look at some of the major slide rule collectors as well as the ISRM shows that Belcher-made slide rules and Gunter scales are fairly rare. So I was both surprised and elated to find recently a Belcher-made slide rule for sale online.

The rule was being sold out of California. And it was not just a standard ruler, not a Gunter’s rule and not a Carpenter’s rule; rather, it was an Engineer’s rule. That is, it has scales that could be called A, B, C, and D, where the first three are two-decade long scales labeled from 1 to 10 to 100, while the fourth scale is a single decade from 1 to 10. The B and C scales are on the slide.


Early American-made Engineer’s Rule, by Belcher Brothers, c. 1835.
Early American-made Engineer’s Rule, by Belcher Brothers, c. 1835.


As can be seen, in addition to the Gunter’s scales there is a table of Gauge Marks on the front for use in a variety of calculations, including for pumping engines. On the back are linear scales, the major one being from 0 to 24 inches when unfolded, in 16-ths of an inch, and other shorter scales in units of 1/4-inch, 1/2-inch, 3/4-inch, and 1-inch. There are also scales along the outside edges of the rule. Along the top edge are two scales, each from 0 to 12 inches, but the top one marked in units of 1/10-inch while the bottom one is in units of 1/12-inch. Along the bottom edge is a single scale from 0 to 100, i.e. marked in units of 1/100-foot.

The Maker’s logo shows that this Engineer’s two-fold boxwood slide rule with brass slide was from the period 1831-1843; and the script-style of the words “New York” suggests it was rather early in that period. Thus it is apparent that this slide rule is earlier than the Palmer’s Computing Scale of 1843.


Close-up of Belcher Brothers rule.
Close-up of Belcher Brothers rule.



8.21.2 Notes on the Brothers Belcher

According to family records,80 the Belcher bloodline can be traced back as far as about 1066, when their ancestors landed in England from Normandy. But let’s move forward to a time at which slide rules were being produced. John Belcher (1719-1785) was born in London to William Belcher, a brewer’s clerk, and Martha Jones. John is recorded living in Birmingham, England, and being married to Sarah Richards in 1760. The couple later relocate to Sheffield, South Yorkshire, where John begins a rule making business. In 1797 John’s son, Zachariah, at the age of 32, is listed as a “rule maker, Purchase Knife maker” in Sheffield, evidently taking up a role in the family business.

Zachariah Belcher married Martha Harborne in 1793. The couple had six sons, five of whom eventually immigrated to the U.S. in the 1820s and 1830s. The oldest three, Thomas, William, and Charles, all immigrated in 1824. Evidently independent round-trips from England occurred earlier than this, as Thomas Belcher was listed in the 1822 New York Directory as “rule maker” at 145 Division Street, when he was 25 years old. Interestingly though, according to the family records, it was apparently William who made a round trip from England to New York in 1821, at age 22, perhaps scoping out the city and registering the family for a future business. In 1824 all three brothers immigrated to the U.S., bringing equipment and inventory from England to be used in the rule-making business.

So officially, Thomas was a “solo” American rule maker from about 1821 and was soon joined by brother William to form the company T. & W. Belcher sometime between 1822-1824. And thus was the apparent start of the production of quality boxwood rules in the U.S., a business that includes Gunter scales and slide rules. The company name was changed in 1831 to Belcher Brothers when brother Charles joined the effort. Note that a Gunter’s scale or Carpenter’s/Engineer’s rule marked T. & W. Belcher would have been made between 1824 and 1831, and would be older than the known Clark & Co. slide rule from 1835 that was noted earlier in our story.

Over the next 12 years, from 1831 to 1843, the company marked its rules in the following ways:81

  • BELCHER BROTHERS MAKERS / NEW YORK
  • BELCHER / BROTHERS/ MAKERS / NEW YORK
  • * BELCHER BROTHERS MAKERS * / * NEW YORK *
  • BELCHER BROTHERS MAKERS NEW YORK

where a “/” denotes a new line for the text that follows it. Our Belcher Brothers rule shown in the above image was made during this period, and bears the second style mark of the list above, with “New York” in a stylish script.

In about 1843 the company moved its manufacturing facilities to New Jersey (though they still had their main offices in New York), and changed the name to Belcher & Brothers, at least for the New Jersey part of the business. By 1853 the entire operation went by the name Belcher Bros. & Co.

Lufkin Rule Company, a popular rule maker that was established in 1869 in Cleveland, OH, but was soon moved to Saginaw, MI, bought the Belcher Brothers company on March 9, 1907. Lufkin was sold to Cooper Industries in 1967, which was later acquired by the Eaton Corporation in 2012.

While five sons immigrated to the U.S., Zachariah and his first-born son, John, remained in England, as well as five daughters. Various descendants of this John Belcher, including an occasional “Zachariah”, continued the original business in England. A 1911 directory shows a “Harold William Belcher (Zachariah Belcher & Sons) Rule Manufacturer” in Sheffield, when Harold was 27 years old. He was quite likely the last to run the England-based Belcher rule business.



As discussed in a previous vignette, the prevalent slide rules being produced in the early 1800s, other than occasional specialty items, were Carpenter’s rules and Engineer’s rules, as well as the standard Gunter scale. These rules were being made primarily in the UK, as Mannheim’s slide rule concept was not presented until 1850 and was not mass produced by Tavernier-Gravet until the late 1860s. And the major German slide rule maker Dennert & Pape did not begin slide rule production until the early 1870s. Thus, it should be no surprise that the earliest makers of slide rules in the U.S. might be a family from England, already skilled in the rule-making business, who immigrated in the early 1800s. The Belcher Brothers Engineer’s Rule c. 1835 in the collection has a special place in the interesting history of the initial development of American-made slide rules.



The earliest American-made slide rules presently collected:


Year Maker Model
1831-1843 Belcher Bros.  Engineer’s Rule
1843 Palmer Palmer’s Computing Scale
1845 Palmer Palmer’s Pocket Scale
c.1858 Stanley No. 15
1902-1912 Dietzgen 1765
1903 K&E 4054
1904 K&E 4041
c.1905 K&E 4035
c.1905 K&E 4041
c.1907 Dietzgen 1762-B
c.1907 Dietzgen 1762-B
1907 K&E 4013 Thacher
1909-1914 K&E 4056






  1. Florian Cajori, A History of the Logarithmic Slide Rule and Allied Instruments, The Engineering News Publishing Company, New York, 1909.↩︎

  2. Florian Cajori, “Aaron Palmer’s Computing Scale”, Colorado College, Colorado Springs, June 1909.↩︎

  3. Thomas Wyman, “When Was The First Slide Rule Produced In The United States?”, Jour. Oughtred Soc., 23.1 p38 (2014).”↩︎

  4. My Ruling Family- The Belcher Brothers & Cos., by Charles Zachary Belcher, Google Books (2013).↩︎

  5. See the web page of antique tool collector Philip A. Cannon II, https://pactu.com/seven0610.2041/2f2fgb.htm.↩︎