C 221 ) 
and confideringthe Refradions in both,) IfoundrheSnnathor.^* 
55'.to be 74°.3o'.in confequciice of the lower Head of^^Thediffe- 
rence of Longitude becwixc thefe two Stars is 17^519': And there- 
fore now the Sun in confequence of the Lucida calct^ ^ 9 2 2 9'. So 
that the Suns motion betwixt the year 1582. the$th. of 
Miir^A at hor.4.42'. and the year isS^.the i$th.of S'f/^/^'^^/'.at hor. 
6. 5 $'*«;^^^(befides the wb©le revolutions) was i87".i6; But the 
Meaf$ motion is 1 9 i^2';greater than the Afpi^rent by 3".46':Which5 
parted in proportion to the Equation of the Earth's motion, col- 
lefied for thofe times from my New Tables, gives the greateft Equa- 
tion of the Orb, T°. 54'. I s", confenting,to my wonder,( without any 
wrefting of the Obfervations)with that,which I deduced from Ca[- 
Jims correft Meridional Altitudes. 
I had not had time to exaoiioe any of thofe others,he hath related j 
nor indeed are they any ways convenient : But by this what I have 
done you may fee/ that if once we get Inftrumenrs to our purpofe, 
that then it will not be difficult tocorreft the Suns motions mihom 
the confideration of the Meridional Altitudes, in which 24feconds 
error gives the place above one minute amifs. 
At prefent I ufe Tables,for the Suns motion, grounded on this E- 
quacion,which is lefs than l}cbos by no lef> than 9 minutes ; Which 
muft needs caufe great alterations in our Numbers for all the other 
Jlanets^in correcting ofwhich,! fiia'll employ fomeof thofe minutes 
I can fpare from my more neceflary ftudies; and have hopes of good 
fuccefs, 
lycho's great Equation made him commit no fmall Errors, and 
put him upon ftrange Ihifts to hide and falve them. All his Cbfer- 
vations of the Planets in their Oppofitions to the Sun, are to be cor- 
reaed,before we may attempt to reprefent them by Numbers : For, 
his Errors in the Suns place made him err fometimes < or 6 hours 
in the time of the Oppofition : which muft be reformed. 
And that I may perform my Difcourfe of the Parallax cf Mars, 
obferv'd,! lhall fall upon it at my fpare hours after Chrifimas. 
Some Obfewations and Experiments made ^md in a Letter communi- 
cated to the Fublijherjor the R.Society the Learned and Inqtd- 
fttive Mr. Martin Lifter. 
I Shall venture to entertain you at prefent wiih a few loofe Notes^ 
which you will be pleas'd to take in good part, and difpofe of 
.them as you think fitting* 
I. of the Efflorescence of certain Mineral Glebes. 
I keep by me certain big pieces of crude AilonvMines,fuch as it 
was 
