Abstract
THE “lurking idea” of Mr. G. C. Thompson, that the moon looks about the size of a fourpenny piece, seems to me to show that those views of it have made most impression on him which he has taken when standing a few feet from the window, when it would cover some such space: while others, with the one foot or two feet idea, have been more wrought upon by unconscious measurement of it against trees in the garden, or house chimneys along the street. I do not think We can get beyond this, in regard to a “personal equation”. As to the apparent difference between the moon near the horizon and the moon in mid-sky, your correspondents have not yet referred to the theory that the felt degree of convergence of the eyes is one help toward measuring distance; which, however, soon ceases as the object is more remote, and the convergence insensible: and that, in looking at the moon along the earth's surface, we feel that she lies beyond this limit by comparison with the objects which intervene, while in looking up through free air there is no such gradation to guide us; that, therefore, we assign, unconsciously, a greater distance to her, i.e., a greater “lurking idea” of estimated magnitude for the same apparent surface, in the former case than in the latter. I write from a dim recollection of one of Sir Sidney Smith's lectures on Moral Philosophy, but I suppose the notion is trite to experts. Is there anything in it?
Article PDF
Rights and permissions
About this article
Cite this article
R., J. Apparent Size of the Moon. Nature 1, 557 (1870). https://doi.org/10.1038/001557a0
Issue Date:
DOI: https://doi.org/10.1038/001557a0
Comments
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.