f 50,3© ) 
to the weight of the Air, which preffing upon the water of the 
veffel makes it rife ia the fi j^hoii, whjift on the other fide it 
defceads by its weight ; M.f/i<^<^«/ fouod ameans tomakethe 
water of the fiphon run, after that the Recipient was exhau- 
fted of Aifj and he fa,w, that with Water 
# iW.Hugens huth made pcirged of Air ^ it did the effed: as well as 
^' r^T'l'^f 'A^r without the Recipients The Ihorteft of 
Caufe of which is hefe r • i ^ . , 
confiWeric/,a6 well with the Icgs of the faphon was eight inches 
Water ft5 TP/^^ Mercu- j^j^g^ and its aperture, oftwohnes. And 
he will not have us doubt, whether the Rex 
cipient was well exhaufted of Air 5 for he did afTure himfelf of 
that, as well by finding that there e^me out no more Air 
through the pump^ as by other more certain marques. 
Ana thishetakesforafurther confirmation of his fupppfii 
tion of a preffing matter more fubtile than the Air^ To which 
he addsj that^ if you take the pains of fearching, to what de- 
gree the force of this preflurereacheth, (which he faith can- 
not be better made than by purfuing the Experiment with 
Tubes full of Mercury yet longer than thofe employ'd by M, 
Boyk^) it will perhaps be found|that this force is great enough 
to caufe ihtV^tGn of the parts of Glafs and of ether forts of 
bodiesj which hold too well together as not to be conjoyned 
but by their contiguity and reft^ai M*DiifCattes would have it. 
Jn ExtraB 
