1. Hooke Robert, An attempt to prove the motion of the Earth from observations (London, 1674). See also Keynes Geoffrey, A bibliography of Dr. Robert Hooke (Oxford, 1960), 30.
2. An Unpublished Letter of Robert Hooke to Isaac Newton
3. ” and therefore we may hence learn, upon what sure grounds all the Astronomers hitherto have built, who have calculated the distance of the Planets from the Horizontal Parallax; for since the Refraction and Parallax are so nearly ally'd, that the one cannot be known without the other, especially by any wayes that have been yet attempted, how uncertain must the Parallax be, when the Refraction is unknown? And how easie is it for Astronomers to assign what distance they please to the Planets, and defend them, when they have such a curious subterfuge as that of Refraction, wherein a very little variation will allow them liberty enough to place the Celestial Bodies at what distance they please.” Hooke Robert, Micrographia (London, 1667), 236. This criticism is repeated in the Attempt: “Now if we are uncertain what part of the observed Angle is to be ascribed to refraction, we are uncertain of the whole observation as far as the possible uncertainty of refraction. Let me have but the liberty of supposing the refraction what I please, and of fixing the proportional decrease thereof according to the various elevation of the Rayes above the Horizon; I will with ease make out all the visible Phenomena of the Universe, Sun, Moon, and Stars, and yet not suppose them above a Diameter of the Earth distant.” Hooke, op. cit. (ref. 2), 15.