[4] While at General Electric from 1909 to 1950, Langmuir advanced several fields of physics and chemistry, inventing the gas-filled incandescent lamp and the hydrogen welding technique.

[5] When this problem was corrected, details that had previously eluded him were revealed, and his interest in the complications of nature was heightened.

Langmuir then taught at Stevens Institute of Technology in Hoboken, New Jersey, until 1909, when he began working at the General Electric research laboratory (Schenectady, New York).

His first major development was the improvement of the diffusion pump, which ultimately led to the invention of the high-vacuum rectifier and amplifier tubes.

A year later, he and colleague Lewi Tonks discovered that the lifetime of a tungsten filament could be greatly lengthened by filling the bulb with an inert gas, such as argon, the critical factor (overlooked by other researchers) being the need for extreme cleanliness in all stages of the process.

Langmuir theorized that oils consisting of an aliphatic chain with a hydrophilic end group (perhaps an alcohol or acid) were oriented as a film one molecule thick upon the surface of water, with the hydrophilic group down in the water and the hydrophobic chains clumped together on the surface.

The thickness of the film could be easily determined from the known volume and area of the oil, which allowed investigation of the molecular configuration before spectroscopic techniques were available.

They introduced the concept of a monolayer (a layer of material one molecule thick) and the two-dimensional physics which describe such a surface.

One of his first ventures, although tangentially related, was a refutation of the claim of entomologist Charles H. T. Townsend that the deer botfly flew at speeds of over 800 miles per hour.

During World War II, Langmuir and Research Associate Vincent J Schaefer worked on improving naval sonar for submarine detection, and later to develop protective smoke screens and methods for deicing aircraft wings.

This research led him to theorize and then demonstrate in the laboratory and in the atmosphere, that the introduction of ice nuclei dry ice and silver iodide into a sufficiently moist cloud of low temperature (supercooled water) could induce precipitation (cloud seeding); though in frequent practice, particularly in Australia and the People's Republic of China, the efficiency of this technique remains controversial today.

In 1953 Langmuir coined the term "pathological science", describing research conducted with accordance to the scientific method, but tainted by unconscious bias or subjective effects.

In his original speech, he presented ESP and flying saucers as examples of pathological science; since then, the label has been applied to polywater and cold fusion.