410
MANUFACTURES.
Manufac- harpsichord wire and which never cross each other,tares. These wavy lines arise from a slight difference in the de-grees of polish occasioned by the unequal action of acidupon the steel. This appearance has been imitated byfalse damasking or etching, but the genuine Damascus blade is distinguished from the false one by grinding,the waving - line being obliterated by this process in thefalse blade, but remaining the same throughout in the realone. In the real blade, indeed, the grinding at firstseems to have destroyed the watering, but it immediatelyreappears by rubbing it with lemon juice.
Alloys of (583.) Alloys of steel. —Very curiousandinstructiveex-
steel> periments on the alloys of steel with several metals, witha view to improve cutting instruments and reflectingmirrors, were made a few years back in the Laboratory ofthe Royal Institution, of which an account is insertedin the 18th Number of the Journal of Science.
Alloys of steel with platinum, rhodium, gold, andnickel may be obtained when the heat is sufficientlyhigh. This is so remarkable with platinum, that it willfuse when in contact with steel at a heat at which thesteel itself is not affected.
There are some very curious circumstances attendingthe alloy of silver. If steel and silver be kept in fusiontogether for a length of time, an alloy is obtained, whichappears to be very perfect while the metals are in thefluid state, but on solidifying and cooling, globules ofpure silver are expressed from the mass, and appear onthe surface of the button. If an alloy of this kind beforged into a bar, and then dissected by the action ofdilute sulphuric acid, the silver appears not in combi-nation with the steel, but in threads throughout the mass;so that the whole has the appearance of a bundle of fibresof silver and steel, as if they had been united by welding.The appearance of these silver fibres is very beautiful ;they are sometimes one-eighth of an inch in length, andsuggest the idea of giving mechanical toughness"to steel,where a very perfect edge may not be required. The mostinteresting result is the following. When one of silverand five hundred steel were properly fused together, avery perfect button was produced, no silver appeared onits surface ; when forged and dissected by an acid, no fibreswere seen, although examined by a high magnifyingpower. The specimen forged remarkably well althoughvery hard; it had, in every respect, the most favourableappearance. By a delicate test, every part of the bar gave
silver. This alloy is decidedly superior to the very best steel, Mechanic 4 'and this excellence is unquestionably owing to combina- Processes,tion with aminute portion of silver. It has been repeatedlymade, and always with success. Various cutting toolshave been made from it of the best quality. Mr. Stodart, avery eminent cutler, assisted at these experiments, whichmust give the public confidence in their practical results.
Equal parts, by weight, of platinum and steel form abeautiful alloy, which takes a fine polish, and does nottarnish ; the colour is the finest imaginable for a mirror.
The specific gravity of this beautiful compound is 9.862.
The proportions of platinum that appear to improvesteel for edge instruments are from 1 to 3 per cent.
While an alloy' of 10 platinum with 80 steel, after lyingmany months exposed, had not a speck on its surface,an alloy of 10 nickel with 80 platinum was in the samecircumstances covered with rust.
The alloys of steel with rhodium would prove highlyvaluable were it not for the scarcity of the latter metal.
Messrs. Stodart and Faraday, in a new Memoir onthese alloys, published in the Philosophical Transactions tor 1822, part ii., observe that “ when pure iron is sub-stituted for steel, the alloys so formed are much less sub-ject to oxidation : three per cent, of iridium and osmiumfused with pure iron gave a button, which, when forgedand polished, was exposed with many other pieces of iron,steel, and alloys, to a moist atmosphere: it was the last ofall in showing any rust. The colour of this compound wasdistinctly blue ; it had the property of becoming harderwhen heated to redness and quenched in a cold fluid. Onobserving this steel-like character, the presence of carbonwas suspected; none, however, was found, although it wascarefully looked for. It is not improbable that there maybeother bodies besides charcoal capable of giving to iron theproperties of steel; and the authors, though they cannotagree with M. Boussirigault when he would replace car-bon in steel by silica or its base, they think his experi-ments very r interesting on this point, which is worthy otfurther examination notwithstanding the above results.
The Editor of the Journal of Science, in commentingupon the above alloys, considers that “ a bar of the bestordinary steel, selected with precaution and most care-fully forged, wrought, and tempered under the immediateinspection of the master, would afford cutting instru-ments as perfect and excellent as those composed ofwootz or of the alloys.”— Journal, xiv. p. 378.
(584.) The following Table shows the Quantities of British Wrought and Cast Iron , TJnwrought Steel, Hardware,and Cutlery exported from Great Britain in each Year, from 1820 to 1831.
Unwrought Iron.
Iron Wire.
Old Iron for re-manufacture.
Unwrought Steel.
Years.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declared
value.
Quan-tity inTons.
Declaredvalue. ■
1820
46,469
£.
449,744
7,937
£.
82,954
5,631
£.
33,648
6,647
£.
106,087
169
£.
7, 019
768
£.
6,476
438
19^809
1821
50,123
434,048
8,484
79,867
7,386
38,456
G,555
92,427
248
10,142
599
4,556
695
30,557
33,044
1822
44,617
356,455
10,665
93,404
8,256
39,008
6,698
97,043
357
13,115
920
6,396
784
1823
45,699
357,959
10,596
90,771
11,304
52,148
7,269
104,096
288
11,150
18
105
654
28,022
1824
38,387
334,534
7,745
73,119
5,370
30,794
9,150
133,389
355
14,117
43
268
734
31,684
1825
25,613
4,835
• 1 •
2,815
5,944
203
72
533
. • •
1826
33,253
. . .
7,163
r • ir
6,563
5,940
189
34
472
. . *
1827
45,284
...
7,337
, .
7,095
6,292
207
30
535
• • «
1828
51,105
• • •
7,449
7,826
6,205
310
108
...
917
. • *
1829
56,178
« • .
6,475
8,931
8,219
329
226
...
714
...
1830
59,885
. . •
8,042
. - .
12,036
8,854
365
884
832
.. •
1831
64,012
.. .
6,191
...
12,444
10,361
538
1,413
...
1,207
- *• 1