146 GERAHÜIREGNERI FOCKENS 



« 2. Thal could we advance towards the stars 99 parts of ihe wholo dislance , and 

 « have onlyjig pari remaining , ihe slars would appear lillle biggcr lo us than lliey da 

 « here. For tliey would shew no othei-wise than thcy do tbrough a tclcscope , which 

 « magnifies an hundred fold, 



« 3. Thal at least nine parts in len, of Ihe space bctween us and the fixed stars can 

 « receive no greater h'ght from the sun, er any of the stars, thao what we have from 

 (I the Stars in a clear night. 



« 4. Tliat hght takes up more time in IraveHing from the stars to us, Ihau we in raaking 

 « a Wesl-India voyage ( which is ordinarily performed in six weeks. ) Thal a sound would 

 « not arrive lo us from Ihence in 50000 years , nor a cannon-bullel in a much longer 

 « time. This is easily computed , by allowing (according to Mr. Newton) ten mi- 

 « nutes for ihe journey of light from the sun hither, and that a sound moves about 1300 

 « foot in a second. 



§ 7. 



Sed hae Polaris observationes , istuc enim revertimur , nou poluerunt non eflicere , ut 

 astronomi persuasum haberent sibi , aliquid variationis ia fixis latere ; quod quäle esset , 

 dici quidem nondum posset , sed tale id tarnen, quod ulteriore digrium esset exaraine. 



Atque ita aecedimus ad Flamsteadium, quem ipsum audire fas est. Celebratissimae 

 ilaque Flamsle adii Kterae, ad W a 1 1 i s i u m missae, sunt hae fere {*)' 



Exordium est a Ricciolo et Tychone , quos parallaxim 24 aut 40 secundorum in Stella 

 Polari Siriove , a se nunc demum deteclam , pinacidiorum vitio frustra quacsituoi 

 afTirmat ivisse. 



« Commodum huic pinacidiorum vitio remedium attulit telescopii , suB initium hujus 

 « seculi, invenlio ; quod omnium (quodscimus) primus distanliis capiendis adhibuit juyenis 

 « ingeniosus GulielmusGascoignius ( praelio prope Eboraciim caesus , 2 Julii 1 644 ) .'* 



Jam ut Wallisio dedit laboris sui conspectum , ita pergit de instrumenlo : 



« Est arcus amplus ferreus , costis etiam ferreis a centro ad circuraferentiam estensis , 

 « et transversis aliquibus necessariis probe munitus , muroque latoritio sub piano meridiani 

 « extructo, firmiter affixus. lllius radius est pedes sex cum unciis octo. Arcus ipse tegitur 

 « superimposita lamina aenea bene crassa , peculiari arlificio accurate planata et polita. 

 « Margo extimus, aliquautulum excavatus, crenis repletur per lotum arcum a circum- 

 u. acta Cochlea incisis; quae cochleäm excipiunt aliam, (ei parem utique et aequalem 

 « qua exscindebantur )^ Haec indicem limbo compingil,. tum etiam circumacta sursum 



« aut 



(*) Johannis Wallis Opera Mathematica. Tom. III, p. 701. TItulus est : Epislola D, Joliaa- 

 nis Flamstead {Mathematici Regii Grenovici) ad D. Wallisium, Dec 3o, 1698, de parailaxi 

 erbis annui telluris observaUif 



