Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/301

 distances, the mutations, or if you please corrections, of a very few minutes, removeth the star a very great way farther off. As for example, in the first of these workings, where the calculation made the star 60. semidiameters remote from the centre, with the Parallax of 2. minutes; he that would maintain that it was in the Firmament, is to correct in the observations but onely two minutes, nay lesse, for then the Parallax ceaseth, or becommeth so small, that it removeth the star to an immense distance, which by all is received to be the Firmament. In the second indagation, or working, the correction of lesse than 4 m. prim. doth the same. In the third, and fourth, like as in the first, two minutes onely mount the star even above the Firmament. In the last preceding, a quarter of a minute, that is 15. seconds, gives us the same. But it doth not so occur in the sublunary altitudes; for if you fancy to your self what distance you most like, and go about to correct the workings made by the Authour, and adjust them so as that they all answer in the same determinate distance, you will find how much greater corrections they do require.

It cannot but help us in our fuller understanding of things, to see some examples of this which you speak of.

Do you assign any whatsoever determinate sublunary distance at pleasure in which to constitute the star, for with small ado we may assertain our selves whether corrections like to these, which we see do suffice to reduce it amongst the fixed stars, will reduce it to the place by you assigned.

To take a distance that may favour the Authour, we will suppose it to be that which is the greatest of all those found by him in his 12 workings; for whilst it is in controversie between him and Astronomers, and that they affirm the star to have been superiour to the Moon, and he that it was inferiour, very small space that he proveth it to have been lower, giveth him the victory.

Let us therefore take the seventh working wrought upon the observations of Tycho and , by which the Authour found the star to have been distant from the centre 32. semidiameters, which situation is most favourable to his purpose; and to give him all advantages, let us moreover place it in the distance most disfavouring the Astronomers, which is to situate it above the Firmament. That therefore being supposed, let us seek in the next place what corrections it would be necessary to apply to his other 11 workings. And let us begin at the first calculated upon the observations of Hainzelius and Mauroice; in which the Authour findeth the distance from the centre about 3. semidiameters with the Parallax of 4 gr. 42 m. 30. sec. Let