1868. ] Metallurgy and Mining. 415 
more or less fine. The analysis of the samples sent to the Imperial 
Geological Institute, has proved in a hundred parts to be— 
era ee tts ot Oe 
AUMINAN ee Meee Na cee g ae) ces SONU P 
Gudnopnonta och et. ee eLy, egy tee 
Water ee a St) a CORE ETteel Pee so Beet 0:7 
The quality of emery is improved in proportion to the larger 
quantity of alumina it contains, and the smaller quantity of silica. 
That of the first quality contains only from 2 to 9 per cent. of silica ; 
that of Asia Minor contains between 60 and 77 per cent. of alumina, 
and between 6 and 33 per cent. of oxide of iron. 
The Coal-field of Johusdorfk (Styria), which was acquired by the 
State im 1842, is worked for a bed of Tertiary coal, and opened length- 
wise to the extent of 3,000 fathoms (5,688 kilometres). It consists 
of 23 grants, on a surface of 288,805 square fathoms, and on an 
extent of 1,500 fathoms (2,644 kilometres) in length, in the direc- 
tion of the bed. The working is carried on partly by open workings 
and partly by pillars; the carelessness and want of method with 
which the ancient proprietors proceeded have caused considerable 
losses of coal by subterranean fires, whose ravages cannot be stopped, 
except by expensive means, which also interfere with the regular 
working. In each of the two principal shafts there is a steam engine 
of 20-horse power, used as much for the exhaustion of the water 
as for the extraction of coal. The annual production is about 
460,000 quintals (a quintal equals 56 kilogrammes), of which 
80 per cent. are consumed by the iron forges of the neighbourhood. 
The workings employ 250 workmen, lodged in houses belonging to 
the State, who are treated in a special infirmary in cases of illness 
or accident. In 1866 the treasury for mutual assistance possessed 
a sum of 30,000 florins. (M. A. Pallausch, ‘Imperial Geological 
Institute, sitting of the 31st March, 1868.) 
The Austrian Geological Survey—chiefly by M. Foetterle and 
M. von Hauer—have prepared a map of the coal-fields of the Austrian 
empire, which has many novelties im its construction. In addition 
to the ordinary geological colouring, the annual coal produce of each 
locality is indicated by differently coloured squares ; and lines of the 
same colour traced along the lines of railway, canals, and navigable 
rivers show the distribution of the coal at a single glance. 
The total annual production of coal in the Austrian empire is 
according to this, the most recent authority, 80,000,000 quintals, 
about 9,000,000 statute tons. 
The boring-machine put into Tincroft Mine, near Camborne, 
Cornwall, by Mr. Déhring, some two or three months since, is 
answering well. It is found to work economically, and, under the 
guidance of two ordinary miners, the end is driven with great faci- 
lity and small cost. General Haupt’s machine, which is a drilling- 
