122 Progress in Scrence. [Januaty, 
transverse, twisting, and shearing stresses; in fact, to all such strains as 
actually occur in engineering works. 
A new mode of tempering steel has been suggested by M. Caron. His plan 
is to plunge the red-hot metal into water heated to about 55° C., and he also 
proposes to restore ‘‘ burnt iron” by a similar process. 
The nature and uses of modern steel formed the text of Mr. Barlow’s 
address as President of the Mechanical Section at Bradford; and although it 
naturally dealt chiefly with mechanical questions, it is yet deserving of the 
metallurgist’s attention. To the same section Mr. Joseph Wilcock con- 
tributed a paper on the Bowling Iron Works at Bradford, in which he traced 
the history of iron-making in this distri@, and gave an excellent description 
of these extensive works. The Bowling and the Low Moor Iron Works, 
both celebrated for the manufacture of boiler-plates, were visited by many of 
the members of the British Association. 
Sir Francis C. Knowles has recently laid before the Society of Arts a de- 
scription of his method of refining and converting cast-iron into either 
malleable iron or steel. His obje& is to effet the conversion without the 
waste of heat and material which attends puddling and other converting pro- 
cesses now in use. Sir Francis employs as his source of heat the combustion 
of gases rich in carbonic oxide, and mixed in due proportion with atmospheric 
air heated to 500°C. Having melted the pig-iron in a cupola with coke or 
anthracite, he collects the gases, frees them if necessary from carbonic 
anhydride, enriches them by addition of free carbonic oxide, and is thus 
enabled to produce by their combustion a temperature of 2500°C. If higher 
heat and greater rapidity be required, he uses the cupola-gases for heating 
his retorts, and employs pure carbonic oxide specially generated, and thus 
obtains a temperature of 2979° C. In either case the mixture of carbonic 
oxide and air is blown into the molten metal, thus producing carbonic 
anhydride and nitrogen at a high temperature ; but this heat may be readily 
utilised, whilst the products of combustion are passed through kilns or retorts, 
containing anthracite or coke, and the carbonic anhydride is thus reduced to 
carbonic oxide, which is again available for combustion. The finery or con- 
verter used in this process is peculiarly constructed, with the view of with- 
standing the high temperature to which it is subjected, and the interior is 
lined with a mixture of protoxide of iron, manganese, emery, bauxite, and 
caustic soda; a highly basic preparation is thus obtained for the lining, as it 
is considered desirable that the cinder should also be basic, not containing more 
than 30 percent of silica. To eliminate the sulphur and phosphorus, caustic 
soda and rich oxide of iron or manganese are employed; and when superior 
iron and steel are to be prepared the use of nitrate of soda or permanganate 
of soda is recommended. It will thus be seen that, so far as the oxidising 
agents are concerned, the process is only a modification of the Heaton process. 
MINERALOGY. 
Two distiné& minerals are known in jewellery as Cat’s-Eye; the one being 
an opalescent quartz enclosing asbestiform fibres, which, lying in parallel 
directions, give the appearance of a fibrous structure to the quartz; whilst 
the other mineral, sometimes called for distin&tion sake, “oriental cat’s-eye,” 
is a fibrous chrysoberyl. Some very fine cat’s-eyes have been received within 
the last year or two from the Cape of Good Hope. These stones are 
generally of a rich brown colour, but occasionally blue, red, and white. Some 
authorities have regarded the Cape cat’s-eye as a form of crocidolite, whilst 
others have supposed that it is only a coloured fibrous quartz; but its true 
character appears to have been determined by Dr. Wibel, of Hamburg. After an 
attentive study of the chemical and microscopical properties of the mineral 
in question, he comes to the conclusion that it is not strictly fibrous quartz, 
but a pseudomorph of quartz after fibrous crocidolite. He shows that the 
so-called brown fibrous quartz, originally described by Klaproth, is merely a 
mixture of pure white quartz with goethite, or hydrous peroxide of iron; 
