( Sm9 ) 
mijm Mem m hac maio animo dicia putes, five In Heuratium (^^l miU 
neqne heneficio neque mmria mtm efl,) five in CL Hugeaium, mem maom 
femper h^hm , at que hSiturus fum^ & amicifme fmper traEhvi • eiufq • L - 
inventorumfmrummn iniqum frerim ^fiimdtor ; nedum in Ferraatium /;^^' 
mum virum : fed m nud<& verimiteflimoniumperhiberem^ Nelioque jam de- 
mortuos nfque ex nofiris omnibus , qtd, jamdiu ante Heuratiam , 'id ivfum 
demonfirmjerm S ^tque, m maU fidei hdear, in ea qmm hac de re mrmio- 
nem frms ediai, Fale> 
Tm other Letters to the fame purpofe with the former : The firB of the Riaht 
Honourable the Lrrd Vif~ count hv.Q^xwck^T ^ Chancellor to her Maiefly 
md Pre/ident of the K.Sockty^ - > 
SIR, 
IT is very fure, that UuF/illiam Neilh^xA in the year i6S7»found out 
and tkmonftrated a Streight line equal to a Paraboloeidi and did 
then communicate and publifh the fame ("though not in print) to my 
felf and others, who ufed to meet ^x. Gre{han^ Colledge, and it was 
there received with good approbations and the fame wa?, prefentiy 
afterwards , otherwife deraonftrated by my felf and others; And 
therefore ancienter than that of Monfieur H^-z^^r^^ which (asitfeemsj 
is not pretended to have been done before the year 1659J and ancienter 
too than that of Sr*C^.^^^;^, finding aStreight line equal toaCycloii 
in the year 1658 i and by him admitted fo to be. Nor ought it at all 
to prejudice Mr. iV^i/, \i\^x.\X,Heuraet'5 was foraewhat fooner abroad 
in print, than that of M.iVW/, (though both in the fame year 1659;) 
fince it is well known to many of us , that Mr. Nell'% was done before* 
Otherwife M.HiSiff^;//, by the fame reafon, will grant the precedency 
to Heuraet, of that which he now claims to be his own invention (that 
Reftifying the Parabolical Line and Squaring the Hyperbolical Space 
domutuaily depend on each other :) for this was publiftied in print 
by yi,Heuraet {or lA.Schooten^or him) in the year 1659, and not by M. 
Hugens till now, J 67 3 : And yet M.iT/^^m thinks, he may well claim 
that invention to be his own, becaufe he now tells us, that he found it 
out about the end of the year 1657, and did (fome time after) com- 
municate it privately to fome friends. And whereas, he doth fuppofe, 
that this invention of his might give occasion to that other of Heuraet-, 
we may alfo as well fuppofe, that he might have taken fuch occafion 
from hearing ofMr.iV^f'/having done the like, (for this had been then 
commonly known for a great while : ) Or might have taken occafion 
(as well as Mr, Neil) from that ofDrJVallis SchoL prop.-^S. Arith, Irfin. 
or from that of Sr.Ck^^r^;^ having found a Streight equal to another 
Curve the year before Or, if it were neceffary to know their fymbo- 
l^zation between the Parabolical Line and the Hyperbolical Space ; he 
might have had k earlier from Dr.frdlis, For, when he had deraon- 
ftrated (i'fWvp'^'f. 38. ^rJ;f^,^.} that the Particles which compofe the 
