Percy Spencer

Percy LeBaron Spencer (1894–1970) was an American inventor and engineer[5][8] who is best known as the inventor of the microwave oven[6]. A New England farm boy who never completed grammar school, he grew up to be one of the world's most successful and respected electrical engineers[1], holding patents for 120 inventions[1] and becoming recognized worldwide as one of the leading experts in microwave technology[7].

Early Life and Education

Percy LeBaron Spencer was born July 9, 1894, to Jasper G. Spencer and Myrtle B. Keene Spencer[8] in Howland, Maine, just 25 miles north of Orono[4]. The childhood of Percy Lebaron Spencer was one of tragedy and deprivation. He was born in a Maine farming community in 1894. His father died when he was eighteen months old, and his mother abandoned him soon afterward, leaving the young Spencer with an impoverished aunt and uncle[7].

His uncle died when Spencer was only 7 years old and shortly after that he had to leave grammar school so he could find a job and earn money to support him and his aunt[2]. At age twelve, Spencer left elementary school to work in a local paper mill to bring much-needed extra income into his household[7]. At the age of 12, he had a job at a spool mill[2].

He was at this job until he was 16 when he heard that a local paper mill would start using electricity which intrigued him. Unable to find anyone that would teach him about electricity (Howland, Maine was a very remote community), he taught himself all that he could and when he applied for a job at the paper mill he was one of three people who were hired to install electricity in the plant[2]. Four years later, after learning that the mill was to become electrified, he volunteered to assist with installing the electrical system, which provided him with a practical education in electrical engineering[7].

Naval Service and Self-Education

Inspired by reports of the efforts of wireless telegraphers to rescue victims of the Titanic disaster in 1912, Spencer developed an interest in radio, a technology then in its infancy[7]. He joined the U.S. Navy at 18 as a radio operator[5]. Joining the Navy as a teenager, he feigned a formal education by teaching himself from textbooks in order to gain admission to radio school[7].

During this time he taught himself a number of scientific subjects, including calculus, chemistry, metallurgy, physics, and trigonometry[6]. Spencer later remembered, "I just got hold of a lot of textbooks and taught myself while I was standing watch at night"[6]. Spencer excelled as a radio engineer and was appointed supervisor of a crew of naval radio operators during World War I[7].

Career at Raytheon

Following his discharge from the Navy, Spencer went to work in the burgeoning radio industry, taking a job with the Radio Corporation of America (RCA) in 1918[7]. In 1922 they founded the American Appliance Company in Cambridge; three years later, the company added Percy Spencer to its three-man staff[1]. In 1922, the Raytheon Company, an early manufacturer of radio components, hired Spencer at the suggestion of his brother John, an engineer with the company[7].

In October of 1925, the company's name was changed to Raytheon ("rai" from the old French "beam of light" and "theon" from the Greek "from the gods")[1]. One of his earliest contributions was a series of improvements to photoelectric vacuum tubes, a major step in the development of the television tube[1]. He helped develop the first gaseous rectifier tube, which made the radio a plug-in appliance[1].

World War II Contributions

When Raytheon was awarded a contract from the Rad Lab at M.I.T. in 1939 to develop radar, Spencer was put in charge[11]. At the heart of radar technology was the magnetron, a tube with cavities that generated microwaves. The production of magnetrons was an expensive and time-consuming series of steps, until Spencer figured out a way to streamline the process, enabling Raytheon to manufacture thousands of magnetrons a day, every one of which was needed for the war effort[11].

The British government had problems manufacturing magnetrons fast enough for the war effort. They could only make 17 per week. Percy Spencer offered to help revise the manufacturing process. After a complete overhaul of the assembly process, he increased the number of magnetrons completed from 17 per week to 2600 per day![4] Raytheon produced 80 percent of the magnetron tubes used in U.S. and British radar during the war[13].

Radar sets Spencer designed were installed in U.S. bombers, where they were powerful enough to spot periscopes on German submarines[1]. With radar becoming increasingly commonplace, the head of Electronics at the U.S. Navy's Bureau of Ships, Commodore Jennings Dow, asserted, "Raytheon radar had a marked effect on every major sea engagement of the war"[6]. For this feat, the US Navy awarded him the Distinguished Public Service Medal[4].

Discovery of Microwave Cooking

In 1945, while working on the active radar set, he noticed that a chocolate that he had in his pocket started to melt. While he wasn't the first to notice this behavior he was curious enough to examine it more thoroughly[2]. Where others might have dismissed the incident as a trivial quirk of the equipment, Spencer saw possibility. His curiosity led him to experiment further, placing popcorn kernels near the magnetron. When they began to pop, his suspicion was confirmed: microwaves could penetrate food and heat it quickly[10].

He experimented with popcorns (which were the first food to be heated with microwaves - deliberately) and with an egg (which exploded)[2]. After that he attached a high density electromagnetic field generator to an enclosed metal box which made a sort of proto-microwave oven in which he conducted later experiments with different types of food[2].

Development of the Microwave Oven

Raytheon patented microwave oven on October 8, 1945 and began development and production[2]. He was later awarded the patent on January 24, 1950[5]. The first commercial microwave oven was called "Radarange," marketed in 1947. It was a different sight from today's microwaves, costing $3,000, weighing about 750 pounds and standing 6 feet tall[5].

The turning point came in 1967, when Amana (a division of Raytheon) introduced the Radarange RR-4. Priced at $495, it was the first compact countertop model, easier to install and affordable for middle-class families[10]. By 1975, microwave ovens were outselling traditional gas ranges, and by the mid-1980s, they were present in over half of all U.S.[10] households.

Professional Recognition and Patents

Dr. Spencer, the fifth employee in Raytheon, was a director emeritus of the company. Following his formal retirement as a senior vice president in 1964, he continued to serve the company actively as a senior consultant[1]. In 1958, Raytheon honored Spencer by dedicating a research laboratory to him in Burlington, Massachusetts. Spencer Laboratory remained an active research facility until 1965 and was still owned and occupied by Raytheon at the end of the twentieth century[7].

Some sources say Spencer earned anywhere from 150 to 300 patents, but my search of U.S. Patent and Trademark Office records found 108 patents between 1932 and 1963[8]. He was eventually awarded a PhD by the University of Massachusetts, an honorary degree, but one that he fully earned by decades of self-education[11].

Personal Life and Character

For his invention of microwave oven, Spencer received no royalties. He was paid a one-time $2 gratuity from Raytheon, which was the same token payment the company made to all inventors on its payroll[2]. In a 1958 Reader's Digest article, an MIT scientist suggested Spencer benefited from his lack of schooling: The educated scientist knows many things won't work. Percy doesn't know what can't be done[13].

Death and Legacy

According to the State of Massachusetts' Massachusetts Death Index, 1970-2003, Spencer died on September 7, 1970[8]. Spencer retired from Raytheon as a senior vice president in 1964 and passed away six years later, unaware the microwave oven would become his signature invention[8]. Many of his obituaries scarcely mentioned his invention of the microwave, citing instead his relatively obscure work in defense and vacuum tube technology[7].

He was inducted into the Inventors Hall of Fame in 1999[5]. Today, over 90 percent of U.S. households own a microwave oven[10], making Spencer's accidental discovery one of the most ubiquitous household technologies of the modern era. As a self-taught inventor who developed his inventions in corporate laboratories, Spencer is also symbolic of the shift in focus from the individual to the corporation that characterized technological research in the developed world during the early twentieth century[7].