The Vara: A Standard of Length With a Not-So-Standard History

By the 1850s, the United States had annexed nearly all of what are now its southwestern states from Mexico, and with the region, its peoples. Though the U.S. government considered this land relatively “unexplored,” it had been dotted with Native American settlements and Mexican haciendas for centuries. The word hacienda was also the name of a unit of measure. Each hacienda was 5 sitios, and each sitio 5,000 square varas (also equivalent to a square Spanish league). The people lived in these dimensions, intuitively understanding distance and size like la palma de la mano (the back of their hand).

Earlier this year, I found myself thinking about an appropriate way to commemorate Hispanic Heritage Month at the National Institute of Standards and Technology (NIST). In my search for ideas, I approached the NIST Museum for a piece of NIST history with a link to Hispanic heritage. As I spoke with research librarian Keith Martin, he said: “We have an artifact of which we only have brief, but intriguing, details … come take a look.” This is how I was introduced to the Mexican vara; I immediately wanted to learn more.

To understand the relevance of the vara in the history of metrology and Hispanic culture, we need to look at its origins. By the mid-15th century, nearly every Spanish province had its own standard length. Then an association of foresters called the “Hermandad de los Pinares” (the Brotherhood of the Pine Forests) from the city of Burgos in northern Spain decided to develop a standard unit of length that would allow them to accurately survey the forests where they harvested timber. Their standard was known as “La Vara de Burgos.” The timber market made the members of the Hermandad very wealthy, and “la vara,” from the Latin virga, which means “rod,” gained widespread acceptance throughout the kingdom. Phillip II declared it Spain’s official standard of length in 1568. By today’s standards, that official vara measures 0.8359 meters (32.909 inches). Traditionally, the physical standard was made of heavy oak and was divided by brass studs into four even sections. Each section was subdivided into units approximately equivalent to the width of two fingers. 

After the conquest of the Americas, the Spanish imposed Andalusian and Castilian measures such as brazas (fathoms), codos (cubits) and palmos (palms) that were adopted by the indigenous peoples with ease, as the units were based on the dimensions of the body, much like their own measures. As it was adopted across Spain, the “Vara de Burgos” likewise became a standard in New Spain. The vara was used to measure not only land, but also the architecture of colonial New Mexico and California. The Catholic Church has historic documents in which buildings’ dimensions are recorded in varas. In colonial California, the vara standard was etched on the Alcalde’s (Mayor’s) Staff of Office, known as the “Barra de la Autoridad.” The vara was used in all of New Spain and was the standard unit of length until the United States annexed all or part of Texas, California, Nevada, Utah, and Colorado from Mexico as a result of the Treaty of Guadalupe Hidalgo in 1848. 

The arrival of the American system of measurement caused confusion and conflict. The American system relied on a square grid for the division of land, while the Spanish used irregular distributions of land that often corresponded with social and political values. For example, closer to a seaport, or for a person of high rank, a vara could reflect the landholder’s importance by being slightly longer. The Americans wanted their property demarcated equally, inch by inch. 

In December 1888, George Julian, surveyor general of the Territory of New Mexico, declared that 90% of the land entries in the territory were fraudulent due to nonstandard measurements. To new arrivals, the variability of the vara would have seemed capricious and frustrating; on top of having sociopolitical dimensions, the Californian, Texan and Arizonan varas were slightly different. For an agrarian society, inconsistently measured land was no small matter. For decades, the clash over land, who owned it, and how to measure it accurately continued. The vara eventually grew so contentious that the U.S. Supreme Court heard cases disputing land with Spanish titles in American territories. The court eventually ruled in 1870 that all varas would be pegged to the Texan vara standard (0.846582 meter or 33.33 inches) for conversion purposes, and many Spanish-American residents lost land to Anglo settlers.

This brings us back to the Mexican varas in the NIST Museum. The Mexican vara is a direct descendant of the Vara de Burgos. The first official Mexican varas obtained by the United States government were acquired by Maj. William Turnbull of the Army Corps of Engineers when the U.S. occupied Mexico City in 1847. These varas were originally intended to be distributed to several Mexican states and were being held in Mexico City during the Mexican-American War. Today, four of these varas are part of the NIST Museum collection. One of the four was presented to the United States Coast and Geodetic Survey in 1847 by the Corps for analysis. Upon its arrival in the United States, the Mexican vara was determined to measure 32.9682 inches at 58.7 degrees Fahrenheit.

All four Mexican varas in the NIST collection are brass-plated iron, presumably to protect against corrosion, and have markings on both sides. One end of the vara is engraved with the seal of Mexico, a golden eagle perched on a cactus while devouring a rattlesnake; the other end reads the year the rods were manufactured, “año 1846.” The other side reads “Vara Mejicana” and “Por Orden Suprema” (by supreme order). Mexican varas are graduated in tenths on one side. One of the tenths is subdivided into 10 centesimos (hundredths), and one centesimo is further subdivided into 10 thousandths. The other side shows division of the vara into one-half, one-third, one-fourth, one-sixth and one-eighth. The one-sixth section is divided into “pulgadas” (Spanish inches). Pulgar is the word for “thumb” in Spanish, and thus the inch roughly corresponds to the length of the first thumb bone. Interestingly, these inches are slightly smaller than imperial inches at approximately 23.26 millimeters (0.92 inch). 

Another finger-derived gradation captured my attention: The varas are also divided into “dedos,” a unit I had never heard of before, which means “fingers.” A dedo is a “standard fingerwidth”; one vara equals 48 dedos. This means that a dedo is approximately 17.45 millimeters (0.69 inch). It is not clear if this unit is of Spanish origin, pre-Columbian origin, or a combination of both. It was common for pre-Columbian peoples to use anthropometric units. 

I can now say things like “I’m approximately 2.15 varas tall,” but this exercise also opened my eyes to something else. I can empathize with the ranchers in the Mexican Southwest regarding their vara and the transition to the standards of the American government. Despite conducting my undergraduate studies, Ph.D. and postdoctoral research in the U.S., as a nonnative English speaker, I still cannot help counting in Spanish or measuring in grams when I cook. I can imagine what changing standards might feel like, even if I cannot imagine the consequences doing so would have on my life. I consider myself lucky because being part of NIST has allowed me to come in close contact with artifacts that had such direct connection to my Spanish forebears, and later to American history. It has been quite a unique, educational and surreal experience.