xil PREFACE. 
furprizing , lazily giving it Credit on his 
bare Word without making Experiments them - 
felves* 
As many of both Sexes * who have not had 
the Advantage of a learned Education , are 
mtwitlftanding greatly defir on s of Knowledge % 
for the Sake of fuch, this Freatife is written 
in Therms mod eafy to be underjlood ; and a 
Jh&rt Account of the feveral Subf ames here 
examined is given for their Information. 
He begs Far don of the Phyjicians and Che - 
pifts, for encroaching now and then on their 
Province, in the Coiirfe of the following Ob- 
fervations and. Remarks; and hopes they will 
generoufty excufe any Mifakes he may have 
fallen into , as he is neither Fhyfician nor Che- 
mi ft. Flpofe too who are thempelves well ac¬ 
quainted with the Subjects here deferibeft will 
not, he hopes, be difpleafed at his endeavouring 
to inftruB fuch as know them not . 
He acknowledges his Obligations to many 
ingenious Friends, who have favoured Mm 
with 
DBS. 
