Grammelogia, or, The mathematicall ring extracted from the logarythmes, and projected circular : now published in th[e] inlargement thereof unto any magnitude fit for use, shewing any reasonable capacity that hath not arithmeticke, how to resolve and worke, all ordinary operations of arithmeticke : and those that are most difficult with greatest facilitie, the extract on of rootes, the valuation of leases, &c. the measuring of plaines and solids, with the resolution of plaine and sphericall triangles applied to the practicall parts of geometrie, horo[l]ogographic, geographie, fortification, navigation, astronomie, &c, and that onely by an ocular inspection, and a circular motion / invented an[d] first published, by R. Delamain, teacher, and student of the mathematicks.

SInce my first publication of the uses of my Mathematicall Ring, or the Logarythmes projected Circular I have beene oftentimes invited by sundry persons for to deliver the way of the projecting, and dividing of the Circles of my Ring upon a Plaine, so that it might bee made in Pastboard to avoyde the charge of the Instrument in metal, for such which have not abilities to buy, and for others, who would first see the practise on it, before they would be at the cost of the In∣strument in metal: for whose sake, and use desiring to satisfie the af∣fectionat, and for a publike benefit, (rather then mine owne particu∣lar) profit, I have caused two Plates of metal to be cut and ingraved, the one containing the Circles of the Projection of my Ring, noted with the letter A. and the other comprehending the Projection inlarged, noted with the letter B. that so they may make use of them more readily, to avoid the labour of dividing the Circles; which schemes being pasted on a Pastboard it is ready for use; And yet further to sa∣tisfie those that are desirous, I have delivered also in the first place ensuing how those Circles are divided, that so they may bee made ac∣cording to any magnitude. In the second place how severall wayes they may be framed into a Ring: In the third place I shew the inlar∣ging of the Instrumentall Invention in these Circles to as great a mag∣nitude for use as may be desired. In the fourth place I deliver se∣verall wayes how these Circles inlarged may bee accommodated for Practicall use. In the fift place, I make a description of the Gramme∣logia, or Instrument in the particular Circles of my Mathematicall Ring, projected on a mooveable and fixed plaine. And in the sixt and last place, I will declare the admirable, and excellent uses of both these Instruments, in the Practicall parts of Arithmeticke, Geometrie, Astronomy, Horolographie, Navigation. &c.