(lis) Kum.i^' 
PHILOSOPHIGAL 
TRANS ACTIONS, 
Munddy , June 4, v666. 
The Gcmtenti. 
Cmain Problems touching fome Points @fNamgatim^ Of a nam 
Centrivance WhccI.Baromctcr,»^a{^A eafier to ha prep^t^d.tbm 
9tbers, Anamunt o/Four Sens which lafely appmredin Frances 
and of em§^unufuatly poJ^ted^Kamhow$,/een in the fame Kingdom. 
A Relation of an Aecident^by Thunder and Lightnings tn Oxford, 
An Experiment i to examine^ what Vigm^ or Celerity of Motim 
hegetteth of imreafetb Light mdlBX^mc. Some Conjiderations 
touching a Letter in the Journal des Scavans of M^y 24, 1666, 
Certain Problems 
ToucMrjgfome PoifftscfNdLYigztlon. 
Hefe Problems are prefented by the Learned and 
^ Induftrious Nicolaus Mercator^ for the advancing 
of that Excellent and Beneficial ScicncejN<?w^«- 
^i««5 as follows : 
The line of Artificid Tangents^ or the Logarithm 
mical Tangent-line, ht^mnmg at 45. deg. andtaki% every half 
degree for a whole one , is found to agree pretty neer with the 
MeridianMne of the Sea.Charte j they both growing, as it were, 
after the fame Proportion. But the T of Meridional degrees 
being calculated onely to every Sexage/frrial minute of a degree, 
ftiews fome Imall difference from the faid LomrithmicalTan- 
gent'line^ Hence it may be doubted , whether that differeritife 
doe not arife from that little erroiir, which is committed by cal- 
culating the Table of Meridional degrees onely to every minute^ 
Gg Mr^ 
