Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/287

 case is not to be supposed. But because (observe well) the distance of the Firmament, in relation to the smallnesse of the Earth, as hath been said, is to be accounted, as if it were infinite; therefore the angle conteined betwixt the two rayes, that being drawn from the points A and E, go to determine in a fixed Star, is esteemed nothing, and those rayes held to be two parallel lines; and therefore it is concluded, that then only may the New Star be affirmed to have been in the Firmament, when from the collating of the Observations made in divers places, the said angle is, by calculation, gathered to be insensible, and the lines, as it were, parallels. But if the angle be of a considerable quantity, the New Star must of necessity be lower than those fixed; and also than the Moon, in case the angle ABE should be greater than that which would be made in the Moons centre.

Then the remotenesse of the Moon is not so great, that a like angle should be * insensible in her?

No Sir; nay it is sensible, not onely in the Moon, but in the Sun also.

But if this be so, it's possible that the said angle may be observed in the New Star, without necessitating it to be inferiour to the Sun, aswell as to the Moon.

This may very well be, yea, and is in the present case, as you shall see in due place; that is, when I shall have made plain the way, in such manner that you also, though not very perfect in Astronomical calculations, may clearly see, and, as it were, with your hands feel how that this Author had it more in his eye to write in complacency of the Peripateticks, by palliating and dissembling sundry things, than to establish the truth, by producing them with naked sincerity: therefore let us proceed forwards. By the things hitherto spoken, I suppose that you comprehend very well how that the distance of the new Star can never be made so immense, that the angle so often named shall wholly disappear, and that the two rayes of the Observators at the places A and E, shall become altogether parallels: and you may consequently comprehend to the full, that if the calculations should collect from the observations, that that angle was totally null, or that the lines were truly parallels, we should be certain that the observations were at least in some small particular erroneous: But, if the calculations should give us the said lines to be separated not only to equidistance, that is, so as to be parallel, but to have past beyond that terme, and to be dilated more above than below, then must it be resolutely concluded, that the observations were made with lesse accuratenesse, and in a word, to be erroneous; as leading us to a manifest impossibility. In the next place, you must believe me, and suppose it for true, that two right lines