GB191500776A - Improvements in Photometers. - Google Patents

Improvements in Photometers.

Info

Publication number
GB191500776A
GB191500776A GB191500776DA GB191500776A GB 191500776 A GB191500776 A GB 191500776A GB 191500776D A GB191500776D A GB 191500776DA GB 191500776 A GB191500776 A GB 191500776A
Authority
GB
United Kingdom
Prior art keywords
mark
lighting
adjusted
light passing
screen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JOHN SIDNEY GORDON THOMAS
South Metropolitan Gas Co
Original Assignee
JOHN SIDNEY GORDON THOMAS
South Metropolitan Gas Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JOHN SIDNEY GORDON THOMAS, South Metropolitan Gas Co filed Critical JOHN SIDNEY GORDON THOMAS
Application granted granted Critical
Publication of GB191500776A publication Critical patent/GB191500776A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/38—Photometry, e.g. photographic exposure meter using wholly visual means
    • G01J1/40—Photometry, e.g. photographic exposure meter using wholly visual means using limit or visibility or extinction effect

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

776. South Metropolitan Gas Co., and Thomas, J. S. G. Jan. 18. Photometric apparatus.-A discriminating photometer for ascertaining whether the lighting in a room or other place conforms to a required standard comprises a tubular casing a fitted with a transparent glass screen g, to which is centrally affixed an opaque disk h having on it a mark, for example a black cross on a white ground, which is observed through an aperture c and a lens d, the work being illuminated by light passing through the glass screen g and reflected back on to the mark by an annular mirror e. When the mark is just visible, the light is of the required strength. The instrument may be adjusted to discriminate a predetermined degree of lighting by means of an iris diaphragm or stop i, which is adjusted to vary the amount of light passing through the screen g.
GB191500776D 1915-01-18 1915-01-18 Improvements in Photometers. Expired GB191500776A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB191500776T 1915-01-18

Publications (1)

Publication Number Publication Date
GB191500776A true GB191500776A (en) 1915-03-18

Family

ID=32648679

Family Applications (1)

Application Number Title Priority Date Filing Date
GB191500776D Expired GB191500776A (en) 1915-01-18 1915-01-18 Improvements in Photometers.

Country Status (1)

Country Link
GB (1) GB191500776A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2652748A (en) * 1951-08-15 1953-09-22 Charles R Croy Optical image focusing apparatus
US20170233199A1 (en) * 2016-01-20 2017-08-17 Rehrig Pacific Company Bakery tray stacker

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2652748A (en) * 1951-08-15 1953-09-22 Charles R Croy Optical image focusing apparatus
US20170233199A1 (en) * 2016-01-20 2017-08-17 Rehrig Pacific Company Bakery tray stacker

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