CONJECTURES.on MAGNETISM 1x. 
Our ancient correfpondence ufed to have fomething 
philofophical in it. As you are now more free from pub- 
lic cares; and I expe& to be fo ina few months, why 
may we not refume that kind of correfpondence? Our 
much regretted friend Winthrop once made me the com- 
pliment, that Iwas good at ftarting game for philofo- 
phers, let me try if I can ftart a little for you. 
Has the queftion, how came the earth by its magnetifm, 
ever been confidered? _ 
Is it likely that zron ore immediately exifted when this 
lobe’ was firft formed ; or may it not rather be fuppofed 
agradual production of time? 
If the earth is at prefent magnetical, in virtue of the 
mafles of iron ore contained in it, might not fome ages 
pafs before it had magnetic polarity? 
Since iron ore may exift without that polarity, and by 
being placed in certain circumftances may obtain it, from 
an external caufe, is it not poffible that the earth received 
its magneti{m from fome fuch caufe? 
In fhort, may not a magnetic power exift throughout 
our fyftem, perhaps through all fyftems, fo thatif men 
could make a voyage in the ftarry regions, a compafs 
might be of ufe? And may not fuch univerfal magnetifm, 
with its uniform dire@tion, be ferviceable in keeping the 
diurnal revolution of a planet more fteady to the fame 
axis? 
Laftly, as the poles of magnets may be changed by the 
prefence of {tronger magnets, might not, in ancient times, 
the near pafling of fome large comet of greater magnetic 
power than this globe of ours havebeena means of chang- 
ing its poles, and thereby wracking and deranging its 
furface, placing in different regions the effeét of centrifu- 
gal force, fo as to raife the waters of the feainfome, while 
they were depreffed in others? 
B.2 Let 
