title: Ground glass differential interferometer.
abstract: With the help of a simple ground glass and a photographic plate the phase variations of a transparent object can be studied. The object is interposed between the source and the ground glass. The photographic plate, kept behind the ground glass, is exposed successively twice, with and without the object. When properly illuminated the negative gives the variation in the derivative of the phase of the object, and this observation can be made in white light.
authors.forename: S
authors.initials: S
authors.lastname: Debrus
authors.forename: M
authors.initials: M
authors.lastname: Françon
authors.forename: C P
authors.initials: CP
authors.lastname: Grover
authors.forename: M
authors.initials: M
authors.lastname: May
authors.forename: M L
authors.initials: ML
authors.lastname: Roblin