AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[THIRD SERIES] 
Art. XXXV.—On Radiant Matter: A Lecture delivered to the 
British Association for the Advancement of Science, at Sheffield, 
Friday, August 22, 1879; by WILLIAM Crooxgs, F.R.S. 
To throw light on the title of this lecture I must go back 
more than sixty years—to 1816. Faraday, then a mere stu- 
dent and ardent experimentalist, was 24 years old, and at this 
early period of his career he delivered a series of lectures on 
the General Properties of Matter, and one of them bore the 
remarkable title, On Radiant Matter. The great philosopher's 
notes of this lecture are to be found in Dr. Bence Jones's 
“Life and Letters of Faraday,” and I will here quote a poe 
in which he first employs the expression Radiant 
“If we conceive a change as far beyond v as as that is 
= ra 80 et also many a would disa 
Faraday was evidently engrossed with this far-reaching 
speculation, for three omg later—in 1819—we find bps od 
ne h evidence and argument to strengthen 
hypot thesis. His notes are now more extended, cad ee Aas 
that in the intervening three years he had thought much and 
deeply on this higher form of matter. He first ~ out that 
matter may be classed into four states—solid, hi anid, tse 
and radiant—these modifications depending ——- 
Am. Jour. Sct.—Tarrp Serres, Vou. XVIIL—No. 106, Oct., 1879. 
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