( -43 ) 
eJ. The Ules of which wiii be not only to (how the true 
time of the Sun's ingrefs into the Tropick and Equinodia! 
Points, but likewifsinto all the o^her Eight Signs ; arnJ fo mil 
ferve for the verifying and rectifying of the Calendar, the 
fame being now fo placed, as that the Perpendicular height 
of the Hole, by which the Light is^idmitced (which is an Inch 
in Diameter) is jooo Inches of the Parifian Foot above ths 
Pavement, and the Meridian Line^ which is as a Tangent to 
it^has the Tangent of 4J Degrees actually divided into loeoco 
Parts upon one of rhe Marble Cheeks that border the Ruler 
or Lath of Lon that expreffes the Meridian Line in the Floor 
of the Churcb,and upon the other Cheek of Marble are mark- 
ed the Degrees, &c, of the Diftance of the Sun from the Ze- 
nith, whereon are alfo marked the Places of the Signs of the 
Ecliptick. From the OWervations made by this Line, Sig. 
Caffini calculated his Tables of Refractions, which have been 
fmce verified by many other Obfervations, both of himfeif . 
and others. 
Thefe Confiderations induced the Sentors of Bcmnia (who 
had the Care of the Edifice of St.Petromo committed to them) . 
to be at the Charge of repairing the faid Meiidian Line, and 
to take care that ic fhould he preTerved for the future.For which 
intent they not only caufed che Inftiuments made ufe of in the 
fixing this Line to be fafely preferved, but they al(b defired. 
Signior Guglielmini to make fo perfed a Defcription of them, 
that in cafe of their Decay^ it might be known how to fup- 
ply and make ufe of them for this Purpofe for the future. 
Which intention and Defire the faid learned ProfelTor has ful- 
ly profecuted and compleated in his Difcouife lubjoined to 
that of Signior CaJJlni^ and he hath alfo added fome ufeful Ta- 
bles, as that of the parts of the Radius, anfwering to the Di- 
vifions of the Tangent into Degrees, Minutes, &c. Secondly^ 
Thtsfe of the Refradions and Rprallaxes of the Sun at feve-. 
ral Altitudes. ThirMy^ A Table of Declination of every P^int 
of the Eciiptick, anf^ering to the Minutes of Declination 
for the prefent Obliquity of the Eciipdck, which he^ makes- 
to be 23^ 29', 12". He adds alfo, That he himfeif by acurate 
Obfervations, finds the height of the Pole at that Church to 
be 44°. %d. 15". which is 1'. if. greater than what S. C^/^ 
/«i had found it in the Year 16 jj. Ail which Particulars^-, 
and divers other very remarkable^ may be found in the Book 
it felf^ to vi/hich therefore 1 refer the Reader. V. A ^ 
