Cary Instruments was founded in 1946 by Howard Cary

Howard Cary

Howard Cary was an American engineer and the co-founder of Applied Physics Corporation , along with George W. Downs and William C. Miller. Before Applied Physics, Cary was employed by Beckman Instruments, where he worked on the design of several instruments including the ubiquitous...

, George W. Downs

George W. Downs

George W. Downs was a co-founder in 1946 of Applied Physics Corporation , later known as Cary Instruments, a division of Varian Medical Systems. The Downs-Lauritsen Laboratory of Physics, on the campus of the California Institute of Technology, is named after him.-References:...

 and William C. Miller under the name Applied Physics Corporation. The company became well known as a supplier of high-quality optical instrumentation for scientific laboratories. The company was purchased in 1966 by Varian Medical Systems

Varian Medical Systems

Varian Medical Systems of Palo Alto, California, is a manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, proton therapy, and brachytherapy. The company supplies informatics software for managing comprehensive cancer...

, at which time it became known as the Cary Instruments division of Varian. Varian still markets a line of optical instrumentation under the Cary brand.

One of the more famous instruments produced in the early days was the Cary-60 CD spectropolarimeter, used to measure circular dichroism

Circular dichroism

Circular dichroism refers to the differential absorption of left and right circularly polarized light. This phenomenon was discovered by Jean-Baptiste Biot, Augustin Fresnel, and Aimé Cotton in the first half of the 19th century. It is exhibited in the absorption bands of optically active chiral...

. Some of these 40 year old instruments are still in daily use in 2005, due to their heavy-duty construction, excellent optics, and lack of any modern replacement.