13 
Ordinary Meeting, October 20th, 1874. 
Edward Schunck, Ph.D,, F.RS., &c., President, in the 
Chair. 
Mr. William H. Johnson, B.Sc., showed two remarkable 
pieces of iron cinder from a furnace in which iron is re- 
heated. The samples showed on one side small dark pris- 
matic crystals which appeared to have been formed in a 
cavity of the cinder as it cooled in the cinder bogie. The 
reverse side of one of them had formed the wall of a second 
cavity ; its surface was however smooth, black, shining, and 
studded all over with the sides of oblong jet-black crystals 
unusually iridescent. He remarked that probably these 
crystals were Fayalite, an iron chrysolite, a mineral found in 
the Mourne mountains in Ireland, which is sometimes iri- 
descent, and whose chemical composition is represented by 
the formula FeoSi 04 . They are the more worthy of notice 
from the rare occurrence of crystals in mill furnace cinder. 
E. W. Binney, F.B.S., F.G.S., said that in Tome XXII, 
No. 9, of the Memoirs of the French Academy of Science, 
MM. B. Renault and Grand’ Eury have published a most 
valuable memoir on the structure of Sigillaria spinulosa, 
and substantially confirmed M. Brongni art’s views of the 
structure of Sigillaria elegans published in 1839. Un- 
fortunately the medulla in both these species was destroyed, 
as is generally the case with specimens of Sigillaria as well 
as the root so long known as Stigmaria ficoides. Professor 
Geoppert and himself many years since described the only 
two specimens of this fossil which showed structure in the 
medulla, and both these specimens were looked upon as 
more than doubtful. Professor W. C. Williamson, F.R.S., 
ill Part 11 of his Memoirs in the Phil. Transactions, p. 215, 
states : “ I have elsewhere called attention to the way in 
PEOCEEDTNes — LiT>. A Phtl. Soc. — Yot„ XIY. — No. 2. — Session 1S7J-5. 
