C »54 ) 
INT RODU CT ION 
T O T H E 
Eleventh Year of thefe TRACTS, 
IN thefcT!?/? years laft: paft) from March 166$^ to this prefent 
Ma:ch 1675, through Gods afliftance I have publifli*t Ni/fC 
final Volumsof Philof&phicd tranfaCiiom ; the Jirji Volum contain- 
ing the Tranfaftions of the firfimd [econdof thofe years ; And now, 
to begin ^ tenth Volum for xhthleventhye^r ( which I intend, 
God willing, to colleft,) I apprehend it my duty in the firft place 
gratefully to acknowledge the Ingemous Suppfyes, which have been 
favourably afforded me, both by our eminent Dome/licks within 
his Majejlies Dominions, and alfo by Forrainers of fome of the beft 
note. 
From our Learn*d Correfpondents from many parts we have re- 
ceived very obliging fatisfaftion, fuchasdothin agoodmeafure 
anfwerour hopes and follicitations publillfbd near the end of the 
Introdufiion of our Fourth Volum. If I may cxprefs it by a refem- 
btance, I may fay ; Some do freely lay out their ftrength and ex- 
qnifite skill to unlock the Cabinets of Nature^ to cleave and break 
up the hardeft rocks, and to draw forth the richeft Ores ; Others 
are bufied in melting them down: Some in refining them, and fome 
in forming them inrodivers kinds ofnecefTary or helpful Utenfils. 
Many hands and heads are bufied to fearch into the Origin of all 
Natural Bodies that are within our Sphsere, or within our Reach ; 
5: ) examine the minuteft principles 5 and to purfue the largeft ex- 
tent, the general afFeftions, ftates, tendencies and inclinations, the 
contents, the feveral kinds, the operations, and the produfiions 
of all the great maffes of Earth, Water, and Air ^ and to extort con- 
fiderable deteftions from them by Fire, and by other curious devi- 
ces, and by Mechanical contrivances. And thefe do fucceed fa 
well, thditi Chjimijlrjf^ v/hichfolongandfolately was obfcured with 
un-intelligibleCantingsand deluding Vapors, is now, in the hands 
of Worthy Philofophers, become oneof the clecreft Interpreters of 
the moft fubtile abftrufities in Nature. Mean while fome are at 
immenfe 
