liad its rife , and whence alfo the Principal Obfei vations of 
th^ change oi its Declination are come to us 5 fo that 'tis juft 
that the Obfervations 5 made elfewhere concerning the famcj 
ibould return thither , as to its fource. 
Ilhall therefore let you know, that having alwayes been 
Curious in the Dodrine of- t\it Load-Stone y after / had made 
the Experiments 5 that are in Gilbertus and others,./ made 
that of the Needles Declination on . three different Meridian- 
Lines, which J. traced An, 1630. in feveral places of Pans^ 
and found , that the Needle declined 4; degr. North eafl : 
which having publifht ^ and made known here t .)the Curious 
sndtoArtifts^ fome oi whom counted 9 or iq degrees accor- 
ding to the Tradition and Writings , of Orcntius Fimuss and 
Cnjlelfranc^j others,. ia\ Jif^rm^ following S^nnertus and o/- 
fufms: all at firft rejected my Obfervation^ and as common- 
ly Newthings meet with obftacles and contradidions , before 
they are eftabliflu,thofe that could not contradid what they faw, 
.pretended 5 that this. Variety did perhaps proceed from the 
greater or lefler vigour in the Loadftones, employed to touch 
with) pr from thence, that the Needles had been touch'^t near- 
er to or farther from their Poles ^ which might make them 
^ decline^ rnore or lefs from Meridian^ (o as a Needle, be- 
ing precifely too^ht by the Pole oi a good ^Lig.net-y might , 
perhaps h^vQ no Decimation at all; 
All which conjedures were not without theit ^probabili- 
ty-, which was the greater , in regard tliat all the Load- 
^jtones 1 had feen,, being rude and like Flints, with irregu- 
lar furfaces^ in bundles aiKl cavities ^ ihdi Poles were al- 
wayes ill pofited, and often within fome 'of the Cavities., 
fo that one could not be fure to ftrike the Ntedle tho- 
row the . Pole of the Stone, To remove which difficulty % 
and at the.fan:je timeto firid another quality ( one of. the ex- 
..jcdlenteft pjf. the World, if true*, ), 'viz^ that .which GiWert 
had affigned to Tfrre/f^^^^ J.refolv'd , to .make the Experi- 
ment of it. And becaufe 7 have not yet written of ic^. nor any 
nian, J know , ( Men, having contented themfelves with re- 
futing this Error by Difcourfe only) you will perhvips; not be 
d^fplf^i/e^ fQ'be informed of the fucc^fs thereof- 
