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 ...

CHAP. XXIX. To find the Diameter, Circumference, Solidity and Superficies of any Sphere or Globe.

TO resolve these Geometrical Propositions, I shall use this Method, viz.

The Diameter of any Sphere, Globe, or Circle, being given to find the Circumference thereof.

Multiply the given Diameter by 22. the Product di∣vide by 7. the Quotient will shew the Circumference required.

Example, Suppose I have a Sphere, Globe, or Circle whose Diameter is 14 Inches: I demand how many Inches it is in Circumference? I say, as 7 is to 22. so is the given Diameter 14. to the required Circumference 44 and so many Inches it's round.

2. The Circumference of any Sphere, Globe, or Circle being given to find the Diameter thereof.

Multiply the given Circumference by 7, the Product divide by 12, the Quotient is the Diameter thereof.

Example, The Circumference aforesaid being 44. I demand how much is the Diameter thereof. I say, as 22 is to 7. So is the given Circumference 44 Inches, to the required Diameter 14 Inches.

3. The Diameter and Circumference of any Sphere, or Globe, being given, to find the Superficies thereof.

Multiply the Circumference by the Diameter, the pro∣duct will be the superficies of the Globe or Sphere, &c.

Example, Let the Diameter be 14 Inches, and the Cir∣cumference 44 Inches, the one multiplied by the other, the product is 616 Inches, and so much is the superficies of the saids Globe or Sphere, as was required.

4. The Diameter of any Sphere or Globe being given to find the Crasitude or Solidity thereof.

Multiply the given Diameter cubicaly, the product multiply (again) by a 11. the last product divided by 21. the Quotient will shew the Crasitude required.

Example, The Diameter of a Sphere or Globe being 14 Inches. I demand how many Inches is contained in its solid capacity? — 14 muliplyed cubicaly, the pro∣duct is 2744. This again by a 11 maketh 30184. which divided by 21. the Quotient is 1437 and 1—3, and so many Inches it is in Solidity, or Crasitude, as was re∣quired.

Here note, that a Cubical foot (that is 12 Inches every way) contains in it 1728 solid Inches.