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XXXVI. 
INCANDESCENT ELECTRIC FURNACES. By J. JOLY, M.A., 
Sc.D., F.R.S., Hon. Sec. R.D.S., Professor of Geology and 
Mineralogy in the University of Dublin. 
[Read Aprit 17, 1901; Received for Publication Apri 19 ; 
Published Jury 6, 1901.] 
Ir is now more than a year ago since I made, for a special purpose, 
a minute electric furnace consisting of a platinum wire imbedded 
in refractory clay. It was obvious that the construction admitted 
of many applications to experimental purposes. In my own case 
I desired to obtain an intense local temperature undisturbed by 
chemical effects, and which might be prolonged for many hours, or 
even days, without risk of serious variation in temperature ; as the 
matter being investigated was the viscous yielding of silicates at 
high temperatures. Postponing for the present an account of the 
special apparatus I then constructed, I proceed to describe the 
principles and mode of construction of the incandescent electric 
furnace which originated in these experiments.' 
Any form suitable to requirements may be given to the furnace. 
If required for fusions, chemical operations, roasting, etc., the 
erucible pattern is most convenient. The conducting wire of 
platinum or manganese steel may be imbedded in the wall of the 
crucible itself, or in the wall of a furnace within which the 
erucible is placed. The latter form is of the most general use 
(see figure). Here an outer vessel of fireclay, lined with a 
reflector, encloses the crucible-shaped vessel in which the wire is 
imbedded, and which may be maintained at a white heat by a 
current. Within this vessel the crucible containing the substances 
being operated on is placed. The inner crucible may obviously 
be of any refractory material, platinum, Berlin porcelain, ete. 
‘ Described in a provisional protection (since abandoned), dated March 15, 1900 
(No. 4892). 
