Curious as much Inrormationj as maybe j in reference to Ba- 
refcQpesi I fliall 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 20tfi 
Pages of my Yhermometrical Experiments and Thoughts, you may 
find, th^t I did fome years agoe think upon this New kind of 
Barofcope; yet the Changes of the Atmofphere's Weight not 
happening to be then fuch, as I wifli'd, and being unwilling to 
deprive my felf of all other ufe of the 
^r^^ Scales here me^nt exaaeft Ballance % that I (or perhaps 
were More competent Eje^ ^ ^^^^ j j confefs tO VOU, 
witnc lies made to turn ma- 1 / rr \- , ^ 
mfefihmththethoufandth ^^^^^ avocations put this at- 
fartofa grain. tempt tor two or three years out of my 
thoughts ; till afterwards returning to 
a place^ where I chanc'd to find t.wo 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 exacSter , yet my defire 
to make the Experiment fome amends for fo long a neglect, 
put me uponconfidering, that if I provided a Glajs^buble ^moxc 
than ordinary large and light, cvenfuch Ballances, as thofe, 
might in fome meafure perform, what I had tried vi^ith the 
ftrangely nice ones above-mention'd. 
Icaufed then to be blown at the Flame of a Lamp fome 
Glafs-buhles as large , thin and light, as I could then procure, 
and choofiag among them one, that feem'd the leaft unfit for 
my turn, I ccunterpoifed it in a pair of Scales, that would loofe 
their /Equilibrium with aboat the 3cth part of a Grain,aGd were 
fufpended at a Fr^me. I placed both the Ballance and the 
Frame by a good Barofcope, from whence 1 might learn the 
prclent w&ight of the Atmolphere. Then leaving thefe Inftru- 
ments together 5 though the Scales, being no nicer than I have 
exprcfs'dj were not able to ftiew me all the Variations of the 
Air's weight,that appear'd in theVI/^^mW Barofcope,yet they 
did what I cxped:ed, by fliewing me variations no greater ^than 
alter'd the height of Quickfilver half a quarter of an 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 accommodatio^Ufjj I .ihould have di- 
fccrned 
