(1-^5) 
high Winds or Calms } whether in ¥/et iveather or dry ? whe- 
ther moft when a North, or when a South , when an Eaft or a 
Weft wind blows? and whether it keeps the fame feafons oi 
Changes ? and whether the feafons and changes of the Air 
and Weather can be thereby difcover'd 5 and the now hiddea 
caufes of many other Ph(v?wmena detected ? 
The faid DoUor is fo much pleafed with the difcovery alrea« 
dy made by the help of this Inftrument^thathe thinlis it to be 
one of the moft wonderful that ever was intheWorldg if we 
fpeak of ftrangenefs,and juft' wonder,and of Phiiofophica! im- 
portance, feparate from the intereft of lucre. For {Jaith he^iu 
one of his Letters) who could ever expect, that we men fliould 
find an Art, to weigh all the Air that hangs over our heads^ in 
all the changes of ic,and, as it were^to weigh^and to diftinguifli 
by weight, the Winds and the Clouds Or, who did believe^ 
that by palpable evidence we fliould be able to prove,the feri-- 
nejl Air to be moft heavyjand the thiekefl Air.aad when darkeft 
Clouds hang neereft to us, ready to diffolve, or dropping, then 
tobelighteft. And though (/<9/;^^0i?j 0/3) we cannot yet reach 
to all the Ufes and Applications of it 5 yet we ihould be en- 
tertained for a while , by the truly Honourable Mr, Boyls , as 
the leading perfon hcreinjUpon the delight and wonder. The 
M^fnet was known many hundreds of years before it was ap"' 
plied to find oui: New Worlds, To me [faith he) tis a wonder- 
ful dclightj -that I have alwaies in my Study before my eye fuch 
a Curious Ballame, 
: Having thusin(>^?i^r^7€xpreffcdhis thoughts about this In- 
vention, and the lingular pleafure 5 he cakes in the Obferva* 
tions made therewith^ he defceods to particulars^ and in feve« 
ral Letters communicates them to his Correfpoodent, as fol- 
lows ; 
I. My WheUhmmeter I could never fill fo exadlly with 
Mercury, as to exclude all Air s and therefore I truft more 
Y to 
