and a fmall white mark, / had made upon this Stone, remained 
Hill in the fame place, where / had put it, without turning at all ? 
whence / thought the Propofition of Gilbert fufficientlv re- 
futed. 
This Stone , having ferv’d me for this Experiment did, toge- 
ther with the greater Stone , (whereof the Poles were alfoweli 
marked) ferve me alfo to find out, whether the Needles, touch- 
ed in different places, nearer to, or further from the Poles, had 
different Declinations. Which having tryed frequently with 
thefe-, and with other Stones, /found no difference at all. in the 
'Declination of the Needles, 
% And now to return to the main fubjeft of the Letter, / then 
obferv’d, that all thefe Needles declined then from the Meridian 
4 1 degrees from the North Haft ward. And, as /did notfufpedh 
that this declination would have changed, having found it to be 
thefame in many places, from Bred in Brittany to the Valto- 
line among the Alpes , / believed, the Antients had ill obferv d, 
and that the want of their exadnefs, in refped either of the 
Meridian- line, or the fabrickof their Needles , or thedivifionof 
their Circles , was the caufe of this defed. But I wasfoon un- 
deceived of my own Error, when / learned a little while after, 
by Letters from England, that Mr. Burrows, Anno 1580, had 
near London obferv’d the declination of the Needle to be 1 1 . 
degr. 11. min. as well as offufius and Sennertus : And that Anno 
X 612, Mr. Gunther, Vroiettox of theMathematicks, had in the 
fame place found that Declination much diminifht, having then 
found but 6 degrees : Andla/lly, that Anno 1 633. Mr. Gellibrand 
had found it but 4. degrees North-eaft, conformable tomyOb- 
fervations, Wbich did allure me, that thofe Declinations were 
not conftant, but had varied. 
And that / might be convinced by my felf, I made from time 
to time Experiments in divers places, and found Hill more and 
more diminution 5 fo that Anno 1660, inffune, after I had very 
exactly traced a Meridian by many Azimuths, before and after 
noon, with a Brafs- Quadrant of 6. foot diameter, and applyed 
good Needles upon it, the one of 7. the other of 10, inches long, 
I found that they declined but one degree, or thereabout : And 
