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he fhould take notice of, and to repeat, fome 
of the Experiments themfelves in their Prefence. 
Monfieur Hllamand’s Paper is in French* but the 
Subftance of it in Englzfh is as follows. 
Experiments made upon glafs "Phials , which break 
with the Stroke of certain Bodies but which 
reffi the Shocks of others , though much more 
ponderous. 
T HE SE Glaflcs have been known fome time, and 
an Account has already been given of them in 
a Diflertation printed at Padua in 1743 : The Ex- 
trad of which Diflertation, publifhed in the Leipfe 
Ads for the Month of February laft gave me alfo the 
Curiofity to repeat in Holland the fame Experiments 
that had been already made both in Italy and fome 
other Places. 
Thefe Glades only differ from ordinary Phials in 
this, that they have not been fet to cool gradually 
in what is called the nealing Furnace, but have been 
immediately expofed to the open Air as foon as 
formed. They may be made of any Shape : I have 
had fome cylindrical with a flat Bottom, others 
of the Figure of a common drinking Glafs, others 
that were conical, and others again elliptic. The 
Experiments have equally well fucceeded upon all 
thefe feveral Glafl.es 5 and all that needs to be obferved 
in the making of them is, to take Care that their 
Bottoms may be thicker than their Sides : And, in- 
deed, the thicker the Bottom is, the eafler do the 
Glafles break. I had one particularly, whofe Bot- 
tom 
