Of Stair-cases.

To make a Complete Stair-case, is a curious piece of Architecture: The vulgar Cautions •re these:

That it have a very liberal Light against all Ca∣•uality of Slips, and Falls.

Page  36 That the space above the Head, be large and Aiery, which the Italians use to call Un bels-fogol•…, as it were good Ventilation, because a man doth spend much breath in mounting.

That the Half-paces be well distributed at com∣petent distances, for reposing on the way.

That to avoid Encounters, and besides to gratifi•… the beholder, the whole Stair-case have no nigar•… Latitude, that is, for the principal Ascent, at lea•…∣ten foot in Royal Buildings.

That the breadth of every single Step or Stair b•… never less then one foot, nor more then eighteen inches.

That they exceed by no means half a foot in thei•… height or thickness, for our Leggs do labour mo•… in Elevation, then in Distention: These I say are fa∣miliar remembrances; to which let me adde,

That the steps be laid where they joyn Co•…•…∣tantino di scarpa; we may translate it somewha•… sloaping, that so the foot may in a sort both asce•… and descend together, which though observed b•… few, is a secret and delicate deception of the pai•… in mounting.

Lastly, to reduce this Doctrine to some Natur•… or at least Mathematical ground, (our Master, 〈◊〉 we see, lib. 9. cap. 2.) borroweth those proport•…∣ons that make the sides of a Rectangular Triang•… which the Ancient School did express in low•… terms, by the numbers of Three, Four, and F•… That is Three for the Perpendicular, from the St•… head to the ground; Four for the Ground-line it se•… or Recession from the wall; And Five for the wh•… Inclination or sloapness in the ascent; which pr•…∣portion, saith he, will make Temperatas gradu•… brationes. Hitherto of Stair-cases which are dire•… Page  37 There are likewise Spiral, or Cockle Stairs, either Circular, or Oval, and sometimes running about a Pillar, sometimes vacant, wherein Palladio, (A man in this point of singular felicity) was wont •…o divide the Diameter of the first sort into three parts, yielding one to the Pillar, and two to the Steps; Of the second into four, whereof he gave two to the Stairs, and two to the Vacuity, which had all their light from above. And this in exact Ovals is a Master-piece.