392 Complete Collection of Kepler's Works. 



Use of Telescopic Sights in Astronomical Observations." In 

 looking over this letter, we find that the number of fasciculi 

 in Hevel's possession was not twenty-two, as stated (or at 

 least implied) by Prof. Frisch, but twenty-nine fasciculi. One 

 thing, moreover, is certain, that Hevel must have possessed 

 all the MSS. ; deriving them from a source where certainly 

 they had received the highest possible attention. In perusing, 

 therefore, the catalogue of these MSS., as given by Hevel in 

 his letter to the Royal Society, we shall find that Prof. 

 Frisch's hopes or expectations as to what the St. Petersburg 

 documents may contain, can be at once answered, because 

 Hevel could never have had less than what is at St. Peters- 

 burg now; though he might have had more, which, however, 

 would make the case worse. A very short time, in fine, will 

 now set the matter at rest. In regard to Kepler's life, Hevel 

 says as follows: — "At Kepleri vitam studio conscriptam non 

 invenio; interim plurima notatu dignissima, vitam ejus spec- 

 tan tia passim notavi, ex quibus vita ejus possit haud obscure 

 depingi. Quae vero in specie ex scriptis ejus penes me habeo, 

 catalogus hicce indicabit" (Ibid.). Whatever fates these MSS. 

 might have subsequently undergone, Hevel's Catalogue must 

 ever be considered the most complete. The extract from 

 Hevel's letters to the Royal Society (as printed in the Phil. 

 Trans.) does not imply any especial offer or request. But 

 there exists among the MSS. of the British Museum, another 

 document relating to these MSS., and this is an autograph 

 letter of Hansch to the Royal Society ; it is dated Vienna, 

 November 20, 1734- . There Hansch speaks of twenty-two 

 fasciculi, and as this was written after his Epistola? ad Keple- 

 rum were published, it may be presumed that seven might 

 have merged (whether entirely or partially is not known) in 

 this undertaking. Hansen's letter contains also a list of the 

 Kepler fasciculi, but they seem to have been re-arranged, as 

 the contents of most, as given by Hevel and Hansch, do not 

 correspond. It is, moreover, curious that Prof. Frisch says 

 that the Epistola ad Keplerum were all that Hansch published, 

 while the letter in the British Museum says, " Praeter Epi- 

 stolas, quae in folio charta augusta prodierunt, et Librum sin- 

 gularem de Calendario Gregorio quern Ratisbone 1726 — in 

 folio pariter typis imprimendum curavi — reliqua MSS. Re- 

 giam desiderant munificentiam." Hansch's letter is entirely 

 lachrymose and supplicatory ; and it is a pity to perceive 

 that these MSS. had something ominous in them, as not only 

 their author, but even several of their subsequent owners fell 

 into deep distress. 

 Having been so far successful in my research, I resolved to 



