Earliest Use of the Term "Bug"

Did you know that Edison invented the use of the term "bug" to refer to a technical problem? The earliest documented use for the term as a technical glitch is found in the Oxford English Dictionary, which quotes a letter to the editor in the 15 September 1875 issue of the journal Operator, "The biggest ‘bug’ yet has been discovered in the U.S. Hotel Electric Annunciator." However, the sentence begins, "'Bugs' on the 'quad' are all very well in their way, but..." What the OED did not understand was that this use of bug was conceived by Edison in connection with his quadruplex telegraph.

Edison invented the quadruplex telegraph, which sent four messages, two in each direction, over a single wire, in 1874. By September 1875, the quadruplex was being used extensively by Western Union. A key feature of the quadruplex was what Edison called a "bug trap."

Describing Bugs

Little of Edison's experimental work on the quadruplex appears in the extant notebook record. Only with the more complete record of his experiments from the Menlo Park Laboratory, which he began operating in April 1876, do we see him using the terms bug and bug trap. During the summer of 1876 Edison uses bug to describe problems in other telegraph systems for sending multiple messages and a new device he called the electromotograph that grew out of his work on recording devices for automatic telegraphs.

For example, in a note on his acoustic transfer telegraph Edison wrote:

Exhibit D shews same with Phila on= These shew where the mysterious bug was: the device for "Earthing" the wire on the low forks was a failure while that on the multiple is a success= Now this explains why all my rinkles failed

Edison's "Bug Trap"

The earliest version of a bug trap (not yet named) can be found in Edison's patent caveat from early August 1873. The term first appears in testimony by Edison in April 1877 during litigation over ownership of his quadruplex. About the same time he began to use it in notebooks describing devices for the quadruplex and for his experimental sextuplex system for sending six messages. "Bug traps" represented one of Edison's key inventive strategies. When he could not eliminate the cause of a problem, he sought an arrangement that rendered the effects insignificant.

Telephone Bugs

The following year Edison began using "bug" to describe technical problems with his telephone experiments. In a 13 March 1878 letter to Western Union President William Orton Edison wrote:

You were partly correct, I did find a "bug" in my apparatus, but it was not in the telephone proper It was of the genus "callbellum" The insect appears to find conditions for its existence in all call apparatus of Telephones.

And writing to William Preece about his telephone on 19 May 1878 Edison noted, "If the static charge is the bug I will go for a compensation."

Bugs in the Receiver

In the fall of 1878, his nephew Charles Edison became the primary experimenter on the receiver and the first person in the laboratory other than Edison to use the term in a notebook entry. Exasperated by the failure of the device to work properly, he drew a "double breasted Bug" and wrote a number of humorous references to bugs. He also described one device to solve these problems as a "Boog Troup."

Edison Defines the Term "Bug"

Soon after he began working on electric lighting, Edison wrote a letter (dated 13 November 1878) in which he provided the best description of his use of bug to describe technical problems:

It has been just so in all of my inventions. The first step is an intuition and comes in a burst— Then difficulties arise. This thing gives out then that. "Bugs" as such little faults and difficulties are called, show themselves— Months of intense watching, study and labor are required before commercial success—or failure—is certainly reached.

The Term Spreads

Some of Edison’s associates began to adopt the term in connection with his work on electric lighting. In a 3 November 1878 letter to Edison, his friend George Barker, a professor at the University of Pennsylvania, complained about Edison’s delay in providing him with one of his new lamps for a lecture, asking Edison, "Have you found a 'bug' in the light, which is the reason why you don’t want me to show it?" Another visitor to the laboratory, Addison Burk, in commenting on a paper about the Edison light delivered at the 21 January 1880 meeting of the Franklin Institute, stated "Mr. Edison calls all difficulties 'bugs.'"

Commercial lamp production, which began in the fall of 1880, was particularly susceptible to bugs. In April 1881, Francis Upton wrote from the lamp factory, "scarcely a day passes without a new 'bug' showing itself." Problems at the lamp factory sometimes required Edison's attention. For example, in February 1882 Edison's secretary Samuel Insull reported that he had been at the factory "a great deal of late & told me a few minutes ago that he thinks he has struck the radical bug in the lamp." In Paris, where Charles Batchelor had established a European lamp factory, bugs also appeared. For example, in July 1882 he told Edison, "I have struck a 'bug' which I am sure is in the glass." Charles Clarke, chief engineer of Edison Electric, warned Edison of a "big bug in Bergmann's brass mounted sockets" that was creating a short circuit.

Other bugs appeared when Edison's new elecrical system was exhibited in Paris and London. In November 1881, when Edward Johnson was setting up Edison's exhibit at the Crystal Palace Exhibition in London, he planned to improve on the record of Edison's earlier exhibit at the Paris Electrical Exhibition explaining that, "The one thing which Paris failed most conspicuously in was 'Reliability' I am therefore 'going for' that 'Bug' more particularly than any other—though there are others almost as important." In response to Johnson's letter, Edison advised him that:

The Belts are liable to slip so you want to look out that all your belts are tight as this is a bad bug when running the machines in multiple arc as if some of the belts are loose the other machines will do all the work and it will be like putting 100 lights on a machine.

Problems also arose at the Pearl Street Station. Soon after it opened in September 1882, Edison had to redesign the coupling for his Jumbo dynamos so that the steam engines that ran them worked together. In his report to Charles Batchelor who was managing the Edison lighting business in Paris, Samuel Insull reported, "Now this bug has been eradicated it would appear that the central station machines will work perfectly." As Edison began installing new stations in 1883, bugs also appeared. Writing from the first of these new stations in Sunbury, PA, William Andrews wrote Edison about "a bug in the dynamo connections" and sent Edison a plan of a new way of connecting spare dynamo, asking him "Please look them over and see if you can find a bug in them."

The Term Becomes Part of Electrical Engineering

The earliest use of the term "bug" appears in an article by James Ashley, the editor of the Journal of the Telegraph. A former partner with Edison in the firm Pope, Edison & Co., Ashley had become a bitter foe of Edison by 1874 when he began calling the inventor "the professor of duplicity and quadruplicity." In his May 1877 article on "Electrical Telegraphic Inventions and Inventors," Ashley noted that "'bugs' are usually numerous in new inventions....This has been demonstrated very forcibly in adapting to practical operation the duplex and quadruplex inventions. The 'bugs' which have been discovered and eliminated would make a large (metaphorical) entomological collection."

By the mid-1880s, Edison's bug trap appeared in books and articles about the quadruplex and another inventor even patented an improvement on "bug-traps" for telegraph receiving instruments.

At the end of the decade, Edwin Houston defined both bugs and bug-traps in his 1889 Dictionary of Electrical Words, Terms and Phrases:

Bug. A term originally limited to quadruplex telegraphy to designate any fault in the operation of the apparatus. This term is not employed, to a limited extent, for faults in the operation of electric apparatus in general.

Bug-Trap. Any device employed to overcome the "bug" in quadruplex telegraphy.

Then in his 1892 Standard Electrical Dictionary, Thomas O'Conor Sloane became the first one to describe "bug" as "any fault or trouble in the connections or working of electric apparatus" and "bug trap" as "a connection or arrangement for overcoming a 'bug.'" But he too noted that these terms were said to originate in quadruplex telegraphy.