Volume 1

The sector on a quadrant, or, a treatise containing the description and use of four several quadrants; two small ones and two great ones, each rendred many wayes, both general and particular. Each of them accomodated for dyalling; for the resolving of all proportions instrumentally; and for the ready finding the hour and azimuth universally in the equal limbe. Of great use to seamen and practioners in the mathematicks / Written by John Collins accountant philomath. Also an appendix touching reflected dyalling [by J. Lyon] From a glass placed at any reclination.

  • Collins, John, 1625-1683.
Date:
1659
Catalogue details

Licence: Public Domain Mark

Credit: The sector on a quadrant, or, a treatise containing the description and use of four several quadrants; two small ones and two great ones, each rendred many wayes, both general and particular. Each of them accomodated for dyalling; for the resolving of all proportions instrumentally; and for the ready finding the hour and azimuth universally in the equal limbe. Of great use to seamen and practioners in the mathematicks / Written by John Collins accountant philomath. Also an appendix touching reflected dyalling [by J. Lyon] From a glass placed at any reclination. Source: Wellcome Collection.

    406/412 (page 26)
    ; l(^ ' Refilled ^Dialling fruit* anf Reclining Glajfc. the tenth houfe or wherein generally it is to be noted. That in all planes which cut the common Interfection of the meridian and Horizon, (as doth the Horizont^, and alfoall meridian planes,botli Direct and Reclining) thefe Circles of Po- fition are all parallel to the meridian, and therefore parallel each to other. For look what refpect the hour-lines in all Direct or Reclinin'’Polar Planes, or Direct meridian Planes have to the Axis of The World: Such refpect have the Circles of Pofition, in all Horizontal, or Direft meridian or Reclining meridian Planes, to the Axis of the Prime vertical: For as the hour-lines in the firft are all parallel to the Axis of the Equinoctial, in whofe Poles they meet: So the Circles of Pofition in the fccond are all parallel to the Axis of the Prime Vertical, in' yrhofe Poles they alfo meet. The reaf6M why Glajfes reflect a double Spet^ is becaufe they ^e polifht on both ftdes^ which may be remedied with a ?\imt%~Jione. T'hofe that dejire to read more of this SubjeH may fee whah is written ^/Kirchcr, in primitiis Gnomicae Catoptricae, and [tnce him by Magnan and othersy ^ A t* £• FINIS, f » * .'i,