Saclise.] 22 [Feb. 1, 



The smaller of the two pieces measures five and three-quarter 

 inches in diameter, and it formed the base of the instrument. It is 

 made of an alloy, of which silver and copper form the chief ingre- 

 dients. In a raised centre it contains a compass, one inch in 

 diameter. The intervening space is arranged in two circles, filled 

 with mythological deities and mythical marine monsters, all finely 

 wrought and chased {ciselirf). 



If we reverse this base, we find beneath it a finely engraved plate 

 heavily gilded with an amalgam of fine gold. It is slightly con- 

 cave. This plate is divided into five panels ; two of these divisions 

 are graduated for different elevations and bear the following inscrip- 

 tion, viz.: " Horologii Achaz hydrographica declinatio ad elevat : 

 Poli 44-45-46, Gradv:" and "47-48-49," respectively. Two 

 others contain pictorial scenes which will be described later on. 

 The helix in the centre, which forms the fifth division, contains 

 the following description, viz.: " Notat concha isthac hemiciclea 

 capitis j8 Esaia tniracvlvm : nam hanc si aqva labrvm vsque impleveris 

 vmbra salts 10 i/no : zo. gradibvs retrorsvin fertvr signvm ac gradv m 

 solis : quin etiam horam dieivvlgarem qvamcvnque vna cvmplanetarimi 

 qvas vacant horls denuncians.^' ( Translation : " This semicircular 

 shell explains the miracle of the 38th chapter of Isaiah. For if 

 you fill a basin altogether with water, the shadow of the sun is 

 borne backward by ten degrees. Moreover, it indicates any com- 

 mon hour of the day whatever, together with that of the planets 

 which they call hours.") 



The larger piece is a basin-shaped plate, made of common brass 

 or gun metal, with a flat, moveable rim one inch wide. Upon this 

 are engraved the signs of the zodiac. On the reverse of this rim, 

 which surrounds the large basin, is engraved the following inscrip- 

 tion : " Christophorvs Schissler, Geometricvs ac Astronomicvs 



ArTIFEX AVGVST.E ViNDELICORVM, FaCIEBAT AnNO 1578." 



The centre or concave part of this plate is ten inches in diameter, 

 and is geometrically divided into the different planetary houses. 

 The depth of the basin is one and three-quarter inches, and the 

 whole once formed the dial of the instrument. 



The rim is surmounted by a brass figure, three and three-quarter 

 inches in height, representing an ancient prophet or astrologer, with 

 the left hand extended so as to hold the " gnomen " used to cast 

 the shadow or to throw the requisite pencil of light. 



This instrument was formerly used, nominally, for calculating 



