32] PAGE 188, LINE 15. Page 188, line 16. _in recta sphaera._--See note
to p. 134.

[233] PAGE 190, LINE 14. Page 190, line 19. _declinans in
Borealibus._--Dipping as it does in northern regions; that is, with the
north-seeking or true-south pole downward.

[234] PAGE 195, LINE 20. Page 195, line 24. _multa maiora pondera._--Many
greater weights. All editions read _multa_, but the sense requires _multo_:
"much greater weights."

[235] PAGE 196, LINE 10. Page 196, line 12. _constans est._--This must not
be read "is constant," for it is constant only in any given latitude.

[236] PAGE 196, LINE 15. Page 196, line 18. _De proportione declinationis
pro latitudinis ratione._--Gilbert here announces, and proceeds in the next
seven pages to develop, the proposition that to each latitude there
corresponds a constant dip to a particular number of degrees. If this were
accurately so, then a traveller by merely measuring the dip would be able
to ascertain, by calculation, by reference to tables, or by aid of some
geometrical appliance, {60} the latitude of the place. In this hope Gilbert
fought to perfect the dipping-needle; and he also worked out, on pages 199
and 200, an empirical theory, and a diagram. This theory was still further
developed by him, and given to Thomas Blundevile (see the Note to p. 240).
Briggs of Gresham College, on Gilbert's suggestion, calculated a table of
Dip and Latitude on this theory. It was found, however, that the observed
facts deviated more or less widely from the theory. Kircher (_Magnes_,
1643, p. 368) gives a comparative table of the computed and observed
values. Further discovery showed the method to be impracticable, and
Gilbert's hope remained unfulfilled.

[237] PAGE 197, LINE 18. Page 197, line 21. _progressionis centri._--Note
Gilbert's precision of phrase.

[238] PAGE 200, LINE 12. Page 200, line 11. _subintellig[=u]tur._--This is
printed _subintelligitur_, and is altered in ink in all copies of the folio
edition. The editions of 1628 and 1633 read _subintelliguntur_. Similarly
in line 14 the word _ducit_ has had a small _r_ added in ink, making it
read _ducitur_, as also the other editions.

[239] PAGE 203. This figure of the experiment with the simple dipping
needle suspended in water in a goblet is due to Robert Norman. In his _Newe
Attractiue_ (London, 1581, chap. vi.) he thus describes it:

"Then you shall take a deepe Glasse, Bowle, Cuppe, or other vessell,
and fill