armil

[Lat. armilla = a bracelet.] [ARMILLA.] Mech. & Astron.: An ancient astronomical instrument. It was of two forms an Equi noctial Armil , constructed with a single ring placed in the plane of the equator, for determining the line of the equinoxes; and a Solstitial Armil , in which there were two or more rings, one of them in the plane of the meridian, for ascertaining the solstices. ( Whewell .)