(407) 
II. Efifiok ad D. Joelem Langelotum de jiLCAL l & 
JCl D I Infisfficienm ad gerendum munta Principiorum 
CorprummtHYalium : Cop^fcripPa a] oh. Bohn fhil, Med, 
D. in Acad. Lipfienfi. Lipfi<Sy A, i6-]S, in%9, 
IN this Epiftle, as the Author declareth himfelf highly dif- 
fatisfied with the Peripatetic^ and Qhjmicd Elements of 
- Bodies naturalj and affirms the Weaknefs of them to have been 
fufficiently laid open, and chiefly by the Experiments of thofe 
two great Englilh Philofophers, Bacm and 
%/^f3 foheunderrakech to prove the In- i7uVTL'L""^''"^r 
r ra ■ r , , » i f a j baih reac/y for the prefs 
fufhciency or that lately celebrated dmrn- a vifeowft of the fame 
virat of Principles, the Alcali and Acid, by /^'^^^ thUEpijiic, 
the congrefs and conflict of which the Mam- ^i^,a femfai of to the 
tainers of them prefume to give an account Fitbujhsr , befon he 
of afl the ph^mmen^ or Nature. rX«t-Xr 
This Undertaking of our Author is here performed , i. By 
reprefenting the Obfcurity of thefe two Principles-. 2. By 
examining fome Inftances in which they are alledged to per- 
form all the elFefts thereunto belongings 9. By (hewing the 
Necefllty of at leaft one Principle more, as aftiveas any of thofe 
two. 
The/r/of thefe he endeavours to make out by taking no- 
tice in tht firfi place , that as yet we have not fo much as com- 
petent Definitions of an Acid and Alcali, and that thofe which 
arc taken from our Senfes are iinfatisfaftory for explaining the 
inward conflitucion of Bodies 5 there being fome fubftances 
endow'd with certain vertuesor powers not difcernable by any 
of our fenfes, and the Acids and Alcali's being capable of 
being reduced into fuch minute particles , as alfo of being 
fometimes thus diffociated by mixtures, 'that the Taft fijall 
ootatall be able to difcover them , and that even in fuch Con- 
crets , whofe aflivity depends from one or other of thofe 
Principles. 
Nexty he confiders, that that affeftion, which is afcribed ro 
thefe Salin Principles, namely ^ their mutual EfFervcfcence , 
is 
