Mechanical waves require a medium to travel through. Examples of mechanical waves are sound waves, water waves, a vibrating string. (See related link). Electromagnetic waves â¦(such as light, radio waves, X-rays, microwaves) do not need a medium to travel through, so these are not mechanical waves.
Photostat definition, a camera for making facsimile copies of documents, drawings, etc., in the form of paper negatives on which the positions of lines, objects, etc., in the originals are maintained. a copy made with this camera.
This article relies too much on references to primary sources. (December 2014) (Learn how and when to remove this template message) The Photostat machine, or Photostat, was an early projection photocopier created in the decade of the 1900s by the Commercial Camera Company, which became the Photostat Corporation.