12 ASTROLABES 



to a very rare type of which, so far as we know, there are no other 

 English examples out of Oxford and which may have been constructed 

 for some member of the early School of Astronomy at Merton College. 

 The chief peculiarity of the type consists in the absence of changeable 

 tablets and of a raised rim round the base plate to contain tablets and 

 rete. They are astrolabes without a mother, and they are combined 

 with quadrants of large size. They resemble the saphea of William 

 Anglicus, 1231. 



The bracket for suspension is missing ; it has evidently been torn 

 away from the notch at the upper side of the thin disc. 



56. Astrolabe or Saphea, Plumb Level and Quadrant. c. 1350. 

 Diameter 14^ inches. Merton College. 

 Brass ; engraved, ' Lat. 52. 6 m Oxonia.' 



57. Astrolabe. c. 1390. 

 Diameter gf inches. Merton College. 



58. Astrolabe. 1527. 

 Bronze. Diameter 6| inches. St. John's College. 

 Inscribed on the back with the name of the maker : 



GEORGIVS HARTMAN 



NORENBERGE FECIT. 



ANNO MD XXVII 



This with other mathematical instruments was given in 1634 to 

 St. John's College by Archbishop Laud, whose arms are engraved upon 

 the back. The bracket is artistically chased with scrolls and two roses, 

 a design which may be seen upon other examples of Hartman's work 

 e.g. on his 1537 astrolabe in the British Museum and on Mr. Lewis 

 Evans's No. 2024 which is stamped GEORGIVS HARTMAN NORENBERGE 

 FACIEBAT ANNO Moxxxxii, and another stamped GEORGIVS HARTMAN 

 NORENBERGAE FACIEBAT ANNO MDXLvin is in the South Kensington 

 Museum. The adoption of 'Tudor' roses as part of the design has 

 been suggested to indicate that these Hartman astrolabes 'were made 

 for English use, possibly for presentation to some royal personage, or for 

 use in the British Navy ' (lonides). But the same design is also charac- 

 teristic of the contemporary work of Johannes Wagner, also of 

 Nuremberg, and, as Mr. Lewis Evans has suggested, was probably 

 copied from an Italian original, of which he has an example in his 

 collection. 



The shackle which is connected with the swivel and ring is also 

 ornamented, and even the shackle-pin is kept in place by a washer 

 designed as a 4-pointed flower. 



Hartman's graduations and finish were finer and more accurate than 

 those of the instruments of his predecessors. 



