MPrSCELEANTOUS<ES SAYS: ; 
appear; and the refult of the ex- 
periment fhowed that {team is in 
fa& a non-conductor of heat; for, 
notwithftanding the cold body ufed 
in this experiment was very large 
and very cold, beinga folid lump of 
ice nearly as large as an hen’s egg, 
placed in the middle of the hollow 
cavity under the bottle, upon a {mall 
tripod or ftand made of jron-wire ; 
yet as foon as the clouds which were 
formed in confequence of the un- 
avoidable introduction of cold air in 
lifting up the bottle to introduce 
the ice, were diffipated (which foon 
happened) the {team became fo per- 
feétly tranfparent and invifible, that 
not the {malleft appearance of clou- 
dinefs was to be feen anywhere, 
not even about the ice, which, as 
it went on to melt, appeared as 
clear and tranfparent as a piece of 
the fineft rock-cryftal. 
This experiment, which I firft 
made at Florence, in the month of 
November, 1793, was repeated fe- 
veral times in the prefence of Lord 
Palmerfton, who was then at Flo- 
rence, and Monfieur de Fontana. 
in thefe experiments the air was not 
entirely expelled from under the 
bottle; on the contrary, a confider- 
able quantity of it remained mix- 
ed with the fteam even after the 
clouds had totally difappeared, as J 
found by a particular experiment, 
made with a view to afcertain that 
faét ; but that circumftance does not 
render the refult of this experiment 
tefs curious: on the contrary, I think 
it tends to make it more furprifing. 
It fhould feem that neither the mafs 
ef fteam, nor that of air, were at all 
cooled by the body of ice which 
they furrounded ; for if the air had 
been cooled (in mafs) it feems 
highly probable that the clouds 
would have returned, 
429 
The refults of thefe experiments 
compared with thofe formerly al- 
luded to, in which T had endeavour- 
ed to afcertain'the motit advanta- 
geous forms for boilers, opened to 
me an entirely new field for fpecu- 
lation and improvement in the ma- 
nagement of fire. They fhowed me 
that not only cold air, but alfo hot air 
and hot fteam, and hot mixtures of 
air and fteam, are non-conduétors of 
heat ; coniequently that the hot va- 
pour which rifes from burning fuel, 
and even the flame itfelf, isa non- 
conductor of heat. 
This may be thought a bold affer- 
tion; but a little calm refleGtion, and 
a careful examination of the pheno- 
mena which attend the combuftion 
of fuel, and the communication of 
heat by fame, will fhow it to be well+ 
founded ; and the advantages which 
may be derived from the knowledge 
of this fact, are of very great import- 
ance indeed. 
On the Danger of ufing Veffels of Lead, 
Coffer, or Brafs,1n Dairies. By Mr. 
Thomas Hayes, Surseon, of Hamfptead. 
From the Letters and Papers of the Bath 
and Weft of England Society for the 
Encouragement of Agriculture, Fe. 
ANY eminent phyficians 
M have afferted, that butter is 
very unwholefome ; while others, 
equally eminent, have confidered 
it as not only innocent, but as a 
good affiftant to digeftion ; and each 
have been faid to ground their epi- 
nions upon experience. Perhaps 
both may be right; and butter may 
be innocent or mifchievous accord- 
ing as it contains many or few ad- 
ventitious materials, colleéted from 
veffels, &c. ufed in the procefs of 
making it. 
lam 
