tends a.Ifo to inorganical ones 5 as is evident from the 
Sympathy offtrings ; ringingofa Giafsto fuch a note> 
as likewifefome Ecchoes anfweringonly certain founds; 
and the like. Themiftake like wife is as great when men 
look upon divers bodys to have their partsin aftate of 
abfolute reft, when as they are in a ftate of tenfion, or 
compreffion. Inftances of this are the fudden cracking 
of GlaflTes that feem to be well neal'd 3 the fcaling of well 
heated Copper ^ the brictlenefs of mixtures of metalls; 
all which and the like probably proceed from contrac- 
tion. The laft main caufe why luch motions are over- 
looked, is our being ufed to the fenfible motions of folid 
bodys when as many effeds proceed from the inteftine 
motions produced in and among the parts of the fame 
body. Such as tools being overheated and by being fo, 
loofing their temper the breaking of optick glalTes in 
grinding; bodys becoming eledrical, and odorous by 
rubbing; and the like ; from all which he concludes, that , 
fuch local motions as are wont to be paft by unobferved, 
may have a notable operation upon fuch bodys as are 
peculiarly difpofed to admit it, and fo have a large fhare 
in natural produdions. 
In the difcourfe of fome unheeded caufes of the falu* 
brity andinfalubrity of the Air,he confines himfelf to the 
imprasgnation it receives fro^i fubtcrraneal ef&uvia. Of 
thefe he niakes two forts, fome conftantly are fenc up in- 
to the Air, which he calls ordinary Emiffions s others 
afcend onely at times, thefe are extraordinary emifSons^ 
thefe again are periodical or fortuitous.This doctrine he 
endeavours to illuftrate by afferting, firft, that in divers 
places the falubrity or infalubrity of the Air confidered 
in the general, may in good part be due to fubterraneal 
expirations, efpecially to thofe he before called ordi- 
nary em^^^lons for this he appeals to experience, which 
finds fome places more healthy then the manifefl quali- 
ties would permit gne to ejped 5 this cfFed: he therefore j 
afcribes 
