OfOXFO%V^SHI%E. zi^ 
help of that exqaifite contriver, Mr. Robert Hook:, commonly 
called the Air Pump ; fo different a thing from the Injlrumentum 
Magdehurgicum^ devifed by Otto Gericke % an ingenious Conful of 
that Refublick,-> that it can fcarce be reckoned an improvement of 
that^ but a new Engine ; although it muft not be denyed but the 
Magdeburg Experiment gave occafion to its Invention. By the af- 
fiftance whereof, th^t Noble Philofop her hdLih accuratly examined 
the Elafiical power ^ prefure^ and weight ; expanfwn and weaknefl 
thereupon, of this element ; and thereby found out fo many 
things nevp^ relating to the height and gravity of the Atmo/phere^ 
nature of a Vacuum ; Flame^ and Excandefcence of coals^ match, 
firing of gun-powder ; propagation of founh ^fluidity ^ light ^freezj 
ing^ reffiration^ (S'C that to give an account of them all according 
to the merits of the Experiments , would be to tranfcribe the 
whole Treatifeo( th^t Honorable Author fet forth on this fubjeft ; 
whirher I refer the Reader for further fatisfadion, and fo to the 
refl of his Works upon feveral other fubjefts ; many of his nume- 
rous inventions and improvements, wherewith he has fo highly ob- 
liged the World, having been made in this place. 
34. Whereof I ftiall mention no more (it being indeed uncer- 
tain as to moil: of them, which were made here, which at London^ 
and which at othtr places^ only the Barometer^ a well known In- 
ftrument, alfo invented here by the fame Noble Per/on^ whereby, 
the gravity of the Jtmo/phere has been daily obferved by the Reve- 
rend and Learned Dr^^ohn Wall':5^ for about fix years together : 
in all which time he found the Quick-filver in the Tube^ never to 
afcend much above 30 inches, and never to defcend much be- 
low 28, which he takes to be the whole latitude oi its variation. 
He alfo obferved, for moft of that time, the temper of the air 
by a Thermometer^ whereof he has ftillthe Notes by him, which 
are very particular for every day. 
35. Which latter /w/?r«OTe«/, though of very ancient inven- 
tion^ there having been one of them found by Robert de Fludiibws 
graphically delineated, in a MS. of 500 years antiquity at leaft ^: 
yet it has ftill received other ufeful advancements (befide that a- 
bove mentioned) from that curious Artifl: Sir Chrifiopher Ifren^ 
who finding the ufual Thermometers not to give fo exaft a meafure 
of the airs extenfion, by reafon the gravity of the liquor as it 
* Gafp.SchottlMagtaVmver.part.-i,. lib.-]-cap.(>. f MofaicalPhilofophyj //^'. i. 2. 
. . _ flands 
