142 GERARDI REGNERI FOCKEKTS 



§ 5. 



Sequilur doctissimus Wallis, qui d«nuo anno 1693 observationem parallaxeos propo« 

 suit et coramendavit amico suo Molyneux ('). 



« Sir! You will, I hope , give me leave ( lliough I have not had the opporlunily of 

 « being persounally known to you) to suggest a speculalion, which hath been in my 

 « thougbls Ihese forty years or raore ; bul I have not had the opportunity of reducing it to 

 « praclice, as being not so well stored with necessary instruments of that kind, nor much 

 « exercised to telescopick observations. And though I have many years since suggested 

 « it to olhers, yet neither have they had leisure or convenienoe of putting it in practice, 

 « It is coiicerning the parallax of the fixed stars, as to the carlhs annual orb 



« That which occurred to my Ihoughts upon Ihese considerations , was to tbis purpose; 

 « that some circumpolar stars ( nearer to the pole of the equator than is our zenith , 

 » and not far from the pole of the zodiack ) should be made choice of for this pur» 

 <( pose. And in case the meridional allalude be discecnably different at Uifferent times , 

 .(( so will also be tfaeir utmost east and west azimutti , which may be better obserrcd 

 « than their rising or setting. And this will be not obnoxious to the refraclion , as if 

 « the meridional altitude ; (for though the refraclion do aßbct the altitude« yet not the 

 « azimuth at all ) ; and we may here have choice of stars för the purpose ; which in 

 x< observations from the bottom of a well we cannot have ; beiag there cooiliied to those 

 « only which pass very near our zerinh , though very small stars. " 



« 1 would Ihea take it for granied , as a Ihing at least very probable , that the fixed 

 « stars are not all ( as was wont to be supposed ) at the same distance from us; but the 

 « distance of some, vaslly greater than of others; and consequenlly , though as to the 

 « more remote , the parallai may be undiscernable ; it may perhaps be discernable in 

 « ihose that are nearer to us. " 



t And those we may reasonably guess ( though we are not sure of it ) to be ncarest to 

 « US , which to US do appear biggest and brightest , as are those of tlje first and se- 

 « cond magnitude; and there are at least of the seeond magnitude, prelly many not 

 « far from the pole of the ecliptick (as that in particular , in the Shoulder of the lesser 

 « Bear). And in case we fail in one , we may try again and again on some other; 

 « which may chance to be nearer to us than what we try Erst. And stars of this big- 

 « ness may be discerned by a moderate tefescope , cven in the day-timej especially 

 « wlien we know just where to look for them. " « The 



(•) Phil. Trans i6g3. XVII. 844 Titiiltis est: A Proposal concerning the parallax of tAe ßied 

 Stars , in reference to the earth's annual oib. In severul leiten o/Majr t , Junjf 29, and iuly 2», 1693, 

 iroai Dr. John Wallis to VViüiain Molyneux, Eiq. 



I 



