( 58 ) 
ment proves the great unreafonabienefs of Mr, Leibnitz s 
Notion. 
I am furpriz’d, that fo careful a Writer as PoUnus 
appears to be, from the accuracy wherewith he deli- 
vers his Experiments, ihould not rather fufpcd his rea* 
ioningin an intricate Cafe, than thus contradi(5t a Prin- 
ciple in Philofophy,v that has been diredly prov’d by a 
multitude o.f Experiments, in particular by thofe 
Sir l^aac Nervton recommends for that purpofe (a) ; and 
that is moreover abundantly cftablilli'd by its exadt 
Agreement with all Obfervations ; as being the Princi- 
ple upon which all appearances, hitherto obferved in 
the motion of Bodies, are accounted for by juft and 
undeniable Arguments^ and w’e fliall find on Inquiry, 
that the prefent Cafe comes alfb under the fame 
Rule. 
As the ufc of Experiments in Natural Philofophy is 
to difcover the Caufes of Things, by exhibiting more 
fimple Eftedfs of thofe Caufes, than occur in the ordi- 
nary courfe of Nature; fo for this end it is necefl'a- 
ry, that our Argumentation upon Experiments be per- 
fedily juft, otherwife they may lead us into Errors. 
The firft' thing neceftary for making right Dedudfions 
from an Experiment, is to determine the proper u;e 
thereof , which I think in this before us is not rightly 
underftood. Certainly this Experiment of Poiems is 
much more fit to inform us of the Law, by which thefe 
yielding Subftances refift the motion of Bodies ftriking 
upon them, than to Ihew the forces, with which Bodies 
ftrike ; for whatever' thofe forces be, the Effedfs muft 
be very different, according to the Difference there 
may be in the Rule obferved by fuch refiftance. 
(<i) Prinelp. Philol, Nat. />. jp. 
Now 
