Curious as much Iuformation 3 as may be, m reference to Ba- 
rofc&pes ; I Hull venture to fend you fome Account of what I 
did but name (in my former Letter) to you. 
Though by a Paflage, you may meet with in the 19th and 20th 
Pages of my Thermometrical Experiments andThoughts , you may 
find, that I did fome years agoe think upon this New kind of 
Barofcope; yet the Changes of the Atmofphere’s Weight not 
happening to bethenfuch, as I wifli’d, and being unwilling to 
deprive my feif of all other ufe of the 
* The Scales here mem exa&eff lallance * 5 that I (or perhaps 
Wire before competent Eye- auyman ; ever had, I confefs to vou, 
wfeftly with the thonfandth that fu r CCeffivC avocations put this at- 
fart of a grain* tempt * or two Gr threc y ears OUt of my 
thoughts; till afterwards returning to 
a place., where I chanc’d to find two or three pairs of Scales , I 
had left there, the fight of them brought it into my mind ; and 
though I were then unable to procure exa&er , yet my defire 
to make the Experiment fome amends for fo long a negle$ 3 
put me upon eonfidering, that if I provided a Glafs-buble ^ more 
than ordinary large and light, even fuch Ballanees , as thofe, 
might in fome meafure perform , what I had tried with the 
ftrangely nice ones above-mention’d. 
I caufed then to be blown at the Flame of a Lamp fome 
Glafs-bubles as large , thin and light, as I could then procure*, 
and choofing among them one, that feem’d the Icaft unfit for 
my turn, I counterpoifed it in a pair of Scales, that would loofe 
their ^Equilibrium with about the 30th part of a Grain, and were 
fufpended at a Frame. I placed both the Baliance and the 
Frame by a good Barofcope , from whence I might learn the 
prefent weight of the Atmofphere. Then leaving tbefe Inftru- 
ments together j though the Scales, being no nicer than I have 
exprefs’d, were not able to fliew me all the Variations of the 
Air’s weight, that appear’d in the Mercurial Barofcope, yet they 
did what I expected, by {hewing me variations no greater ,than 
alter'd the height of Quickfilver half a quarter of aii Inch, and 
perhaps much fmaller,than thofe;Nor did I doubt, that, if I had 
had either tender Scales, or the means of fupplying the Expe- 
riment with convenient accommodations, I fliould have di- 
