258 
in the Government laboratory in Paris. Experiments conducted 
at very high temperatures, or states in which they recognised 
and adopted certain standard points, such as the following, are 
four in number :— 
I. 1175° (Violle) The melting point 
of Platinum ... ae ... Is sufficient to reduce to a vitreous 
mass Anorthite, Leucite, Olivine 
II. The melting point of Steel ... Melts all felspars except Anorthite, 
and all the bisilicates 
III. 1054° (Violle) The melting point 
of Steel and Copper ... Melts easily Augite and Nepheline 
IV. 1000° (Violle) The melting point 
when Copper fuses with 
difficulty. 
Some colour destinations in general use, are indispensable 
for many purposes. “The student,” says Faraday, “will do 
well to observe the appearances of a furnace or a substance, as 
it rises from a dull red heat to the highest possible temperature 
that can be given to it; to form in his mind a clear idea of the 
colour and appearance of the light emitted in succession; and 
to select three or four distinct periods of the ignition to serve 
him as it were for degrees. The terms dull red, red, full red, 
yellow, white, bluish white, or any others he may choose, should 
not be quite indefinite, but so far understood and appreciated, 
and the appearance he intends to express by them so fixed in his 
mind, that he may be able to say whether a fire is above or 
below any required degree; or having registered a particular 
heat by its appearance in his note book, that he may be able to 
attain it again with considerable accuracy.” (Chem. Manip. 
Faraday, 3rd ed. page 146.) 
In degrees In degrees 
Cent. Fahr. Cent. Fahr. 
Nascent Red ... ... 525° ... Lowest ignition of iron 
Dark Red “ie Serer ALOE eee (in dark) ... acai eoais *635° 
Cherry Red_... ... 900°... Ironbrightred(indark) ... *752° 
Deep Orange Red... 1100° ... ‘Tron red hot (in twi- 
White ... re lode Ras light) 506 rose? Uiess 884° 
Glowing White ... 1500° ... Red fully visible in th 
day ... “ee ; 1077° 
Heat of acommon fire... 1141° 
(J. Jamin) (Daniels) 
