Ouranoskopia, or, The contemplation of the heavens, in a perpetual speculum, or general prognostication for ever wherein is succinctly demonstrated the names and natures of the signs, planets and aspects, terms of art, order of the spheres, the colours, magnitudes, motions, solid proportions and distances of the seven planets from the earth ... / by Iames Corss ...

First, by Calculation.

Lift up your Quadrant towards the Tower or Steeple whose Altitude you require, untill you behold (through both the sights) the very Summity or Top; which found, mark well the Divisions or Points in your Square, which the Threed and Plummet did fall on: And if they be of right shaddow (that is to say when the Threed and Plummet falls on that side of the Square which is next the sights) Then say, As the Parts out, is to the whole Scale. So is the length of the Base, to the Altitude of the Tower: And therefore multiply the distance from you to the Base by 12. the product divide by the

parts cut (by the fall of the Plummet) the Quotient will show you the Altitude required. — But if the Threed fall upon the contrary shaddow, then say, As the whole Scale is to the parts cut, So is the length of the Base, to the Altitude required. And therefore multiply the Base by the parts cut, the product divide by the whole Scale, and the Quotient is your desired Al∣titude above the Level of your Eye.

Example, Suppose the Threed with the Plummet should happen to fall on 6 parts of contrary shaddow, and the distance from your standing to the Base of the Tower be 120 foot: I say,— As the whole Scale 12, is to the parts cut 6, So is the length of the Base 120 foot, to the Altitude of the Tower 60 foot. Thus mul∣tiplying the Base 120, by the parts cut 6, the product 720 divided by 12, the Quotient is just 60, and so many foot high is that Tower or Steeple above the Level of your Eye.