20 
Steam Etigme. 
ricas connected with fluidity, and vapour or steam, lowe 
to the 6th edition of Dr. Henry’s chemistry, which is 
not yet commonly known in this country. The second 
extract, I have taken from Gregory’s treatise on mechanics, 
theoretical, practical, and descriptive, Vol. 2, The tables 
of Betancourt and Dalton, are from Prony’s architecture 
hjdraulique, and the 5th voL of the Manchester transac- 
tions. The account I shall give of the history of the 
steam engine, I shall adopt from Gregory, Hornblower, 
and Playfair. Gregox*y’s account in his Encyclopaedia, 
and his plate to that account which I have adopted, are 
abridged and borrowed from the article steam engine in 
the Edinburgh Review, and Nicholson and Tilloch’s Ma- 
gazines. And I again request my readers to turn to the 
excellent articles, steam,” and “ steam engine” in that 
Encyclopaedia (Dobson’s edit.) asindispensible to be care- 
fully perused, by those who would acquire knowledge 
on the subject, notwithstanding the illiberal remarks of 
Gregory and Hornblower on that article and the compiler 
of it. 
Caloric the Cause of Fluidity, 
I. The temperature of melting snow^ or of thawing ice^ 
is uniformly the same at all times^ and in all places , — ■ 
This may be ascertained by the thermometer, which will 
always, when immersed in liquefying ice or snow, point 
to 32^ of Fahrenheit, whatsoever may be the height of 
the barometer, or the elevation, above the sea, of the place 
where the experiment is made. (Shuckburgh, Philosophi- 
cal Transactions, Ixix.) 
II. The sensible heat^ or temperature of ice^ is not 
changed by liquefaction,— K thermometer in pounded ice 
stands at 32®, and at the very same point in the water 
which results from the liquefaction of ice. 
