[ao] 
certain that the weight of Air^ to that of Water ^ is nearly as r 
to 800, whence tlie weight thereof, to that of any Project is 
given ; tis very hkely, that to the fame Velocity, and Mag^ 
nituie, but of different matter, the Opfofttwn fhould be rect^ 
frccally as the weights of the fhott ; as Ukewife that to fliott 
4:}f the fame LV/6?;//7 and matter, but of different Sizes, it 
j'liould be as the Dimteters reciprocal)' : whence generally the 
Qjfofmon to fliott with the fame Velocity, but of differing D/- 
rmeters, md Materials^ fhould be as their Specifck Gravities 
into their 'Diameters reciprocally ; but whether the O^pofition, 
to differing Velocities of the iame fliott, be as the Squares of 
thole Velocities^ or as the Velocities themielyes, or otherwife, 
is yet a harder Queftion. However it be, tis certain, that 
in large Shott of Mettal^ whofe weight many Thouland times' 
Surpaifes that of the Air^ and whole force is very great, in 
proportion to the Surface wherewith they prefi thereon ; this 
Oppofitio'a is fcarce difcernable : For by feveral E<:perirnents 
made with all Care and Circumfpeftion with a Morterpeice 
Extraordinary well fixt to the Earth on purpofe, which car- 
ried a Solid Brafi Shott of 4^ Inches Diameter, and of about 
14 Pound weight, t\iQ Ranges above and below Degrees 
were found nearly equal; if there were any diiference, the^ 
under went rather the fartheft, biit thoft differences 
were ufually left than the Errours committed in ordinary 
Frattice, by the unequal Goodnefi and Drynefi of the fame 
fort of Pouder, by the Unfitnefs of the Shott to the Bore^ and 
by the Loofnefs of the Carnage. 
In a Smaller Brafs-Shott of about an Inch and half Diameter y 
caft by a Crofs-Boiv which, ranged it, at moft about 400 foot^ 
the Force being much more Equal than in the Morterpeice^ 
this difference was found more Curioufly, and Conftaritly 
and moft Evidently, the under Ranges out went the upper. 
From which Trials I conclude, . that altho' in fmall and light 
Shott J the Oppofition ol the Air^ ought and muft be accounted 
for ; yet in Shooting of Great and Weighty Bombs^ there need 
Ijc very little or no allowance made ; and lb thefe Rules may 
be 
