(227) 
Upon which the Aif may be thought endow'd with Hidde^^ quali- 
ties, he efteems to be thofe Exotick effluviums, that probably do 
proceed partly from beneath the Surface of the Earth, partly frora 
theCeleitial Bodies ; not denying meanwhile, that the Air may, e- 
fpecially at fome times and in fome places,derive multitudes of effi- 
cacious particles from its own operations, a<9:ing as a Fluid fub- 
Aance upon that vaft number and variety of Bodies that are imnie- 
diately expofed to it. Now,thereConjeftures,grounded upon 5'«^'- 
^w^i^^*/?/ and ^/^(fr^^/ Effluviums, are inthLsTra(S confirmed by 
many ccnfider able and hitherto un heeded Obfervations 5 and they 
arefuch, that,if they prove to be well-grounded, they may lead usj 
(as the Author alfointimatcs,Jto other Sufpicions of no mean confer 
quence; As i. That they may make us confider, whether divers 
Changes of Temperature and Conftitution in the Air, not on-y as to 
mmifefl^ but as to the more /^^^/^f qualities, may not fometimes in 
parr, if not chiefly, be derived from the paucicv,or plenty, and pe- 
culiar nature of one or both of thofe forts of Effluviums ? 2. That 
they may fuggefl to us, as a thing not altogether improbable, that 
fome Bodies,vve are converfant with,may have a difpofition and fit- 
nefs to be wrought on by,or to be affociated with,fome of thofe Ex* 
otick effluvia, that are emitted by unknown bodies lodged under 
ground, or that proceed from this or that Celeflial body. 3. That 
they may put us upon the Invefl:igation,Whether among the Bodies 
we areacquainted with here below, there may not be found fomr, 
that may be Receptacles, if nor alfo AttraSlives^ of the Sidereal and 
other Heterogeneous effluviums that rove up and down in the Air? 
All which fuggeftions arc countenanced in this Piece with divers 
un-common Obfervations. And from the laft of thefe three,occafion 
is taken, in a peculiar Difcourfe,^o enquire,Whether5as *tis thought 
no impofliblc thing,that Nature fiiould make^ fo it may not be an un- 
prafticableor hopelefsrhing, that Mif;; fhould^^/i, or^r^fhould 
frepare, ufeful Magnets of the Exotick effluviums of the Lower re- 
gion of the Earth, or the Upper of the World ? 
To this firftparc are fubjoyned i. Some Obfervations of the 
Growth ofMetals,i€nd'\r\g to refol ve thislnquiry , i^'/^. whether a por- 
tion ofMatter, wherein as yet noMetal,or but fuch or fuch a quantity 
of ir,canbe found,this being expos'd to the Air,willafter a timeei- 
therafFord fome Mettal where none appear'd before, or a greater 
proportion of it than it had before. 2, Some New Experiments about 
the Frefervationof Bodies in Vacuo Boyliano, or with exclufion of the 
Air 5 tryedupon Bread^Milk^Cream^Cheefe^Ko^iJled meat ,Blood,Vio' 
