160 Report on the Geological Survey of Connecticut. 
work, apparatus is under construction to put the invention into ope- 
ration.’—(On the application of the Hot Blast, in the manufac- 
ture of Cast Iron, by Tuomas Cuarx, M. D., Professor of Chem- 
istry in Marishal College, Aberdeen. ‘Transactions of the Royal 
Society of Edinburgh, Vol. xiii, p. 373.) For additional details 
respecting this improvement, see a treatise ‘on the use of hot air in 
the iron-works of England and Scotland, translated from a report 
made to the Director General of mines in France, by M. Dorrenoy, 
in 1834. London. Murray. 1836.’’* 
Bog ore is abundant, and has long been wrought in the State, 
particularly in the central and eastern parts. 
The iron works of Stafford produce 350 tons of cast iron annu- 
ally—but a part of the iron comes from Massachusetts. 
- Spathic tron.—Of this ore, there is a great deposit at Roxbury, 
near New Milford. This ore consists of more than half protoxide 
of iron, and the rest is carbonic acid with a little manganese, lime 
and magnesia. 
This mine was wrought, many years ago, for silver, and then deep 
and expensive excavations were made, of the origin of which Mr. 
Shepard has given an interesting account. ‘This ore is usually 
called the steel ore, because it affords steel directly from the bar 
without cementation, and its nature has in this case been repeatedly 
verified of late years by the fabrication of cutting instruments from it. 
lyon pyrites are found in many parts of the State, and the mag~ 
netic variety in abundance in the towns of Trumbull, New Fairfield, 
and Litchfield ; in the latter town, it is particularly abundant. It is 
easily converted into copperas, but as yet there is no manufactory 
similar to that which is so well known at Stratford in Vermont, 12 
miles west of Dartmouth College. 
Copper.—Most of the ores of copper are found in Connecticut ; 
and there have been many exportations, particularly in the early 
part of the late ‘century. 
A mass of native copper, weighing nearly 100 pounds, was found 
a few miles from New Haven, many years ago; and more recently 
(about 20 years ago) near Wallingford, one weighing 6 pounds, 
which is in the cabinet of Yale College, and it has been discovered 
repeatedly in Farmington. ‘The excavations formerly used as a 
State Prison, in Granby, were made a century ago, in digging for 
* The greater part of the extracts commencing at the top of the preceding page; 
was printed in Vol. xxxi, at p. 181 of this Journal, but we allow them to stand here 
again for the sake of the connexion. 
