I ^^3 3 
the Anfwcr of Dr. Papinf^? fez^eral OhjeSiions made 
by Mr. Nuis againfi his Engine for raifwg Water 
by the rarefaSlion of the Air ^ whereof a defcription 
is given in No. 178. of thefelranfaSiions, 
Having feen in the Nmvelles de U Refubl. des Lettres of 
the Month of Decemhr laii, fome difficulties which 
Mr. Niiis doth fiad in m) new way for raifing Water^pub- 
lifh'ciu the Phiiolbphica! Tranlatlions of me month of 
"Januarys I am obUged to anfwcr them as clearly as I can 
in thefe lliort notes. 
In his firrt Ob)eQ;ion he faith, that it would be a very 
hard matter to hinder but fbme Receptacles would come 
to be fiird too much : Sa that the water fiUing alio the 
pipes C D D would hinder the effeft of the Engin, To 
this I anfwer that it being necelfary to let out the water 
ofthehigheft Receptacle, I thought it might be conceived 
that the water may alio be let out of the inferiour Recep- 
tacles by inferting into each of them a crooked pipe, reach- 
ing a pretty way downwards, and having its lower aper- 
ture fnut up with a valve ; whereby the water might run 
out when the Receptacle fhould be fiU'd to a certain height; 
and fb I did not ludge it needful! to prevent this Objeft- 
i ion. 
The (econd Difficulty, which I had very well forefeen 
/ as it is plain in my firft explication ) lyes in the great 
' quantity of Air to be rarefied : So that Mr. Nuis^ by his 
computation, doth find that the Pump's fhould every one 
rcontain,84 cubick feet of rarefied Air to raile water at 
12000 footdiftance. To this I may aniwer, firft that I have 
not pofitively promifed a good fuccefs but for Windfor and 
St.Qernmn ; but whenllpoke oiVeYfMes\\&di the word 
I ferhapSy thereby flhewing that before any one fhould go 
1 about fuch a great undertaking he fhould reflect vpon 
