Letter | Published:

Illusion of Convergent Beams of Light

Nature volume 141, page 1059 (11 June 1938) | Download Citation



IN a recent letter1 under this title, Dr. A. H. Rosenthal describes an optical illusion produced by the rotating beam from a lighthouse. We studied this phenomenon last year2, and we think that both perspective and photometry are required for its explanation. Diffusion laws show that the brightness of the beam is great near the opposite horizon; this fact, together with the apparent convergence, gives to the observer a strong impression that the light-house is just beneath the horizon.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    NATURE, 141, 836 (1938).

  2. 2.

    and , Comptes rendus, 204, 1882 (1937).

Download references

Author information


  1. Ecole Polytechnique, Paris V. May 16.

    • G. COLANGE
    •  & Y. LE GRAND


  1. Search for G. COLANGE in:

  2. Search for Y. LE GRAND in:

About this article

Publication history





By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.