Chapter C: D E F are the four printing cylinders, named in the order of their (12)

_Copper and Arsenic_ form a white-coloured alloy, sometimes used for the scales of thermometers and barometers; for dials, candlesticks, &c. To form this compound, successive layers of copper clippings and white arsenic are put into an earthen crucible; which is then covered with sea salt, closed with a lid, and gradually heated to redness. If 2 parts of arsenic have been used with 5 of copper, the resulting compound commonly contains one tenth of its weight of metallic arsenic. It is white, slightly ductile, denser, and more fusible than copper, and without action on oxygen at ordinary temperatures; but, at higher heats, it is decomposed with the exhalation of arsenious acid. The white copper of the Chinese consists of 40·4 copper; 31·6 nickel; 25·4 zinc; and 2·6 iron. This alloy is nearly silver white; it is very sonorous, well polished, malleable at common temperatures, and even at a cherry red, but very brittle at a red-white heat. When heated with contact of air, it oxidizes, burning with a white flame. Its specific gravity was 8·432. When worked with great care, it may be reduced to thin leaves, and to wires as small as a needle. See GERMAN SILVER, _infra_.

Tutenag, formerly confounded with white copper, is a different composition from the above. Keir says it is composed of copper, zinc, and iron; and Dick describes it as a short metal, of a grayish colour, and scarcely sonorous. The Chinese export it, in large quantities, to India.

COPPER, WHITE, or _German silver_. M. Gersdorf, of Vienna, states, that the proportions of the metals in this alloy should vary according to the uses for which it is destined. When intended as a substitute for silver, it should be composed of 25 parts of nickel, 25 of zinc, and 50 of copper. An alloy better adapted for rolling, consists of 25 of nickel, 20 of zinc, and 60 of copper. Castings, such as candlesticks, bells, &c., may be made of an alloy, consisting of 20 of nickel, 20 of zinc, and 60 of copper; to which 3 of lead are added. The addition of 2 or 2-1/2 of iron (in the shape of tin plate?) renders the packfong much whiter but, at the same time, harder and more brittle.

Keferstein has given the following analysis of the genuine German silver, as made from the original ore found in Hildburghausen, near Suhl, in Henneberg:--

Copper 40·4
Nickel 31·6
Zinc 25·4
Iron 2·6
-----
100·0

Chinese packfong, according to the same authority, consists of 5 parts of copper, alloyed with 7 parts of nickel, and 7 parts of zinc.

The best alloy for making plummer blocks, bushes, and steps for the steel or iron gudgeons, and pivots of machinery to run in, is said to consist of 90 parts of copper, 5 of zinc, and 5 of antimony.

A factitious protoxide of copper, of a fine red colour, may be made by melting together, with a gentle heat, 100 parts of sulphate of copper, and 59 of carbonate of soda in crystals, and continuing the heat till the mass become solid. This being pulverized, and mixed exactly with 15 parts of copper filings, the mixture is to be heated to whiteness, in a crucible, during the space of 20 minutes. The mass, when cold, is to be reduced to powder, and washed. A beautiful metallic pigment may be thus prepared, at the cost of 2_s._ a pound.

All the oxides and salts of copper are poisonous; they are best counteracted by administering a large quantity of sugar, and sulphuretted hydrogen water.

The following scientific summary of copper ores in alphabetical order may prove acceptable to many readers, amid the present perplexing distribution of the native metallic compounds in mineralogical systems.

1. _Arseniate of Copper._

A. _Erinite_, rhomboidal arseniate of copper, micaceous copper, _kupferglimmer_. Emerald green; specific gravity 4·043; scratches calc-spar; yields water by heat; fusible at the blowpipe, and reducible into a white metallic globule. Soluble in nitric acid; the solution throws down copper by iron. It consists of arsenic acid 33·78; oxide of copper 59·24; water 5; alumina 1·77. It is found in Cornwall, Ireland, Hungary.

B. _Liroconite_; octahedral arseniate of copper; lens ore, so called from the flatness of the crystal. Blue; specific gravity 2·88; scratches calc-spar. It consists of arsenic acid 14; oxide of copper 49; water 35. It is found in Huel-Mutrel, Huel-Gorland, Huel-Unity, mines in Cornwall.

C. _Olivenite_; right prismatic arseniate of copper; olive-ore. Dull green; specific gravity 4·28; scratches fluor; yields no water by heat; fusible at the blowpipe into a glassy bead, enclosing a white metallic grain. It consists of arsenic acid 45, oxide of copper 50·62. It affords indications of phosphoric acid, which the analysts seem to have overlooked. It occurs in the above and many other mines in Cornwall.

D. _Aphanese._ Trihedral arseniate of copper. Bluish green, becoming gray upon the surface; specific gravity 4·28; scarcely scratches calc-spar; yields water with heat; and traces of phosphoric acid.

The fibrous varieties called wood copper, contain water, and resemble the last species in composition.

2. _Carbonate of Copper._

A. _Azurite_; kupferlazur. Blue. Crystallizes in oblique rhomboidal prisms; specific gravity 3 to 3·83; scratches calc-spar, is scratched by fluor; yields water with heat, and blackens. Its constituents are, carbonic acid 25·5; oxide of copper 69·1; water 5·4. The Chessy and Banat azurite is most profitably employed to make sulphate of copper.

B. _Malachite_; green carbonate or mountain green. Crystallizes in right rhomboidal prisms; specific gravity 3·5; affords water with heat, and blackens. It consists of carbonic acid 18·5; oxide of copper 72·2; water 9·3.

C. _Mysorine_; anhydrous carbonate of copper. Dark brown generally stained green or red; conchoidal fracture; soft, sectile; specific gravity 2·62. It consists of carbonic acid 16·7; oxide of copper 60·75; peroxide of iron 19·5; silica 2·10. This is a rare mineral found in the Mysore.

3. _Chromate of Copper and Lead_; vauquelinite. Green of various shades; specific gravity 6·8 to 7·2; brittle; scratched by fluor; fusible at the blowpipe with froth and the production of a leaden bead. It consists of chromic acid 28·33; oxide of lead 60·87; oxide of copper 10·8. It occurs at Berezof in Siberia along with chromate of lead.

4. _Dioptase_; silicate of copper; emerald copper. Specific gravity 3·3; scratches glass with difficulty; affords water with heat, and blackens; infusible at the blowpipe. It consists of silica 43·18; oxide of copper 45·46; water 11·36. This rare substance comes from the government of Kirgis.

The silicate of Dillenberg is similar in composition.

5. Gray copper ore called Panabase, from the number of metallic bases which it contains; and Fahlerz. Steel gray; specific gravity 4·79 to 5·10; crystallizes in regular tetrahedrons; fusible at the blowpipe, with disengagement of fumes of antimony and occasionally of arsenic; swells up and scorifies, affording copper with soda flux. Is acted upon by nitric acid with precipitation of antimony; becomes blue with ammonia; yields a blue precipitate with ferrocyanide of potassium; as also indications frequently of zinc, mercury, silver, &c. Its composition which is very complex is as follows: sulphur 26·83; antimony 12·46; arsenic 10·19; copper 40·60; iron 4·66; zinc 3·69; silver 0·60. Some specimens contain from 5 to 31 per cent. of silver. The gray copper ores are very common; in Saxony; the Hartz; Cornwall; at Dillenberg; in Mexico; Peru, &c. They are important on account both of their copper and silver. _Tennantite_ is a variety of Fahlerz. It occurs in Cornwall. Its constituents are, sulphur 28·74; arsenic 11·84; copper 45·32; iron 9·26.

6. _Hydrated silicate of Copper_; or Chrysocolla. Green or bluish green; specific gravity 2·03 to 2·16; scratched by steel; very brittle; affords water with heat, and blackens; is acted upon by acids, and leaves a siliceous residuum. Solution becomes blue with ammonia. Its constituents are silica 26; oxide of copper 50; water 17; carbonic acid 7.

7. _Muriate of Copper._ Atakamite; green; crystallizes in prisms; specific gravity 4·43. Its constituents are, chlorine 15·90; copper 14·22; oxide of copper 54·22; water 14·16; oxide of iron 1·50. The green sand of Peru, collected by the inhabitants of Atakama, is this substance in a decomposed state.

8. _Oxide of Copper._

A. Black, or Melaconise; a black earthy looking substance found at Chessy and other places. It is deutoxide of copper.

B. Protoxide or red oxide of copper; ziegelerz. Crystallizes in the regular octahedron; specific gravity 5·69; scratches calc-spar; fusible at the blowpipe into the black oxide; and reducible in the smoke of the flame to copper; acted upon by nitric acid with disengagement of nitrous gas; solution is rendered blue by ammonia. Its constituents are oxygen 11·22; copper 88·78. It occurs near Chessy, and upon the eastern slope of the Altai mountains.

9. _Phosphate of Copper._ Dark green; crystallizes in octahedrons; specific gravity 3·6 to 3·8; scratches calc-spar; yields water with heat; and affords metallic copper with soda flux; acted on by nitric acid. Its constituents are, phosphoric acid 28·7; oxide of copper 63·9; water 7·4. It occurs at the mines of Libethen in Hungary.

10. _Pyritous Copper_; Kupferkies; a metallic looking substance, of a bronze-yellow colour, crystallizing in octahedrons which pass into tetrahedrons; specific gravity 4·16; fusible at the blowpipe into beads attractable by the magnet, and which afterwards afford copper with a soda flux; soluble in nitric acid; solution is rendered blue by ammonia, and affords an abundant precipitate of iron. Its composition is, sulphur 36; copper 34·5; iron 30·5; being a combined sulphuret of these two metals. This is the most important metallurgic species of copper ores. It occurs chiefly in primitive formations, as among gneiss and mica slate, in veins or more frequently masses in very many parts of the world--Cornwall, Anglesea, Wicklow, &c. It is found among the early secondary rocks, in Shetland, Yorkshire, Mansfeldt, &c. The finest crystallized specimens come from Cornwall, Derbyshire, Freyberg, and Saint Marie-aux-Mines in France.

11. _Seleniate of Copper_; Berzeline. Is of metallic aspect; silver white; ductile; fusible at the blowpipe into a gray bead, somewhat malleable; is acted upon by nitric acid; consists of selenium 40; copper 64.

12. _Sulphate of Copper_; Cyanose. Blue; soluble, &c. like the artificial sulphates, which see.

_Brochantite_ is a subsulphate of copper observed in small crystals at Ekaterinenbourg in Siberia.

13. _Sulphuret of Copper_; Kupferglanz. Of a steel gray metallic aspect; crystallizes in rhomboids; specific gravity 5·69; somewhat sectile, yet brittle; fusible with intumescence at the blowpipe, and yields a copper bead with soda; soluble in nitric acid; becomes blue with ammonia, but lets fall scarcely any oxide of iron. Its constituents are, sulphur 19; copper 79·5; iron 0·75; silica 1·00. It occurs in small quantities in Cornwall, &c.

The chemical preparations of copper which constitute distinct manufactures are, Blue or Roman vitriol; for which see _Sulphate of Copper_; Scheele’s green and Schweinurth green, Verditer, and Verdigris. See these articles in their alphabetical places.

COPPER, _Statistics of_.--Copper ores may be imported into Great Britain for smelting, from any country, and under any flag. On arrival of the cargo at Swansea or elsewhere, a bond is given at the Custom-house, which binds the party to return the quantity of copper which the lot of ores shall be ascertained to contain, into bond within a limited period, or pay thereon the duty as foreign copper, which is 27_l._ per ton. The cargo of ore is then weighed out by the custom-house officer, and samples are taken which are sent to two assay-masters in Cornwall, the highest produce of the two being entered as that of the cargo. This fixes the quantity of copper that must be exported under the bond.

The copper produced from foreign ores must then find a market, as cake or pig copper, in France, Holland, Germany, Italy, the United States of America, &c. At Calcutta, it is subject to a duty of 6 per cent.; and at Bombay, to a duty of 10 per cent. _ad valorem_.

The export of British unwrought copper to the continent of Europe, and to the United States of America, was formerly inconsiderable. These countries drew the bulk of their supplies either from the north of Europe, or direct from South America in pig copper. In point of fact, the copper derived from the import of foreign ores for smelting, has produced for itself a new market, as the following table, taken from the official returns will show.

Export of unwrought copper from Great Britain to all parts, except Asia:--

Years ending Jan. 5th. 1830 881 tons.
-- 1831 857 --
-- 1832 1326 --
-- 1833 2471 --
-- 1834 2523 --
-- 1835 3267 --
-- 1836 4083 --
-- 1837 2546 --

In the last year, that ended with 5th January, 1838, the export of unwrought copper was about 5000 tons.

Let any candid and practical man consider attentively this table, and compare it with the import of foreign ores for the same period, and with the gradual advance in the value of copper; and then let him, if he can, avoid the conclusion that the admission of foreign ores for smelting was a great boon conferred upon the British copper mines, for it made this country what it now is, the regulator and distributor of the copper produce of the world--the country to which all others consuming and not producing copper, must look for a regular, certain, and economical supply. We want the admission merely under proper and safe regulations, of foreign copper for refining, to draw to this country the whole supply of copper for the world, by which prices would be regulated and maintained, and our copper-mining interests put beyond the reach of successful rivalry.

This country did not furnish any supply of unwrought copper to the continent of Europe, or to the United States of America, which was worthy of notice, before the year 1830; in fact, previous to that time, we imported considerable quantities of foreign copper for re-exportation to India. It is easy to explain how the produce of foreign ores, being prohibited from export in any other shape, has, in fact, opened for itself a new _debouché_, and this is illustrated by the table, showing the growth of the export of unwrought copper from 1830. To prove that this is not merely a simultaneous advance in the export of all sorts of copper, a corrected table is subjoined from the official returns, comprising the whole export, and divided so as to illustrate the operation of the copper produce of foreign ores upon our foreign copper trade.

Copper exported:--

+-----------------+--------+----------------+----------+
| |Wrought.| Unwrought. | Total. |
| Years ending +--------+-------+--------+----------+
| | To all | To | To all | To all |
| | parts. |India. | parts. | parts. |
+-----------------+--------+-------+--------+----------+
| |_Tons._ |_Tons._|_Tons._ | _Tons._ |
|5th January, 1825| | | 960 | |
| 1826| | | 1/2| |
| 1827| | | 130 | |
| 1828| | | 1329 | |
| 1829| | | 1079 | |
| 1830| 5327 | 1801 | 2682 | 8,009 |
| 1831| 6172 | 2317 | 3150 | 9,322 |
| 1832| 5171 | 2423 | 3714 | 8,885 |
| 1833| 5855 | 2312 | 4569 |10,424 |
| 1834| 5417 | 1769 | 4019 | 9,436 |
| 1835| 4787 | 2104 | 5283 |10,072 |
| 1836| 5948 | 1993 | 5935 |11,883 |
| 1837| 6105 | 1588 | 3909 |10,014[17]|
+-----------------+--------+-------+--------+----------+

[17] Supplement to the Mining Journal, Feb. 28. 1838.

Production of Copper in Great Britain:--

+---------+-------+----------+
| Years. | Ores. | Metal. |
+---------+-------+----------+
| |_Tons._| _Tons._ |
|1771-1781| 28,185| 3380 |
|1781-1791| 32,854| 4123 |
|1791-1801| 48,034| 4083 |
|1801-1811| 67,533| 6060 |
|1811-1816| 78,237| 7181 |
| 1816 | 83,058| 7045 |
| 1817 | 75,016| 6608 |
| 1818 | 80,525| 6714 |
| 1819 | 92,234| 7214 |
| 1820 | 92,672| 7364 |
| 1821 | 98,803| 8163 |
| 1822 |106,723| 9331 |
| 1826 |128,459| -- |
| 1827 | -- |12,381 |
| 1828 |153,600|12,169 |
| 1829 | -- |11,994 |
| 1830 | -- |13,097 |
| 1831 | -- |14,480 |
| 1832 | -- |14,463[18]|
+---------+-------+----------+

[18] Taylor’s Records of Mining, Part I., p. 171.

Quantity of Copper produced in the several districts of Great Britain and Ireland:--

+----------------------+--------+--------+--------+--------+--------+
|With Ores from-- | 1828. | 1829. | 1830. | 1831. | 1832. |
+----------------------+--------+--------+--------+--------+--------+
| | _Tons._| _Tons._| _Tons._| _Tons._| _Tons._|
|Cornwall | 1966 | 9763 | 10,890 | 12,218 | 12,099 |
|Devonshire | 434 | 318 | 368 | 312 | 249 |
|Other parts of England| 71 | 36 | 10 | 31 | 42 |
|Island of Anglesea | 738 | 901 | 815 | 809 | 852 |
|Other parts of Wales | 259 | 172 | 237 | 123 | 237 |
|Ireland | 706 | 790 | 768 | 972 | 974 |
|Isle of Man | -- | 4 | 9 | 15 | 12 |
| | ------ | ------ | ------ | ------ | ------ |
|Total copper from the | 12,169 | 11,994 | 13,097 | 14,480 | 14,465 |
|ores of the United | | | | | |
|Kingdom | | | | | |
|Copper smelted from | -- | 30 | 124 | 100 | 56 |
|Foreign ores | | | | | |
| | ------ | ------ | ------ | ------ | ------ |
|General total | 12,169 | 12,024 | 13,221 | 14,580 | 14,521 |
+----------------------+--------+--------+--------+--------+--------+

_Statistics of Copper for Cornwall in 1837._--The total quantity of ore sold was 142,089 tons (of 21 cwts.), yielding an average produce of eight per cent.; the quantity of fine copper being 11,209 tons 1 cwt.; and the average price of the ore 5_l._ 15_s._ 6_d._; the total amount of the sales for the twelve months being 822,516_l._ The standard upon the 5th of January was 127_l._ 16_s._; this was the highest for the year. Upon the 22d of June it was at the lowest, being only 93_l._ 18_s._ It went up again to 120_l._ 10_s._ upon the 5th of October; but declined with some slight fluctuation to 107_l._ 18_s._ upon the 28th of December. The largest quantity sold at any one ticketing, was 4670 tons, upon the 4th of May: and the smallest 1088, upon the 17th of August. The highest produce was nine and five-eighths per cent. upon the 13th of July; and the lowest, seven, upon the 26th of January. The greatest weekly total was 25,887_l._, upon the 2nd of November, and the least 5694_l._ upon the 17th of August. The average sum per week was 15,817_l._[19]

[19] Mining Review, Feb. 28, 1838.

Table of the produce of Copper Ores and fine Metal in Cornwall, from 1800 to 1830.

+------+---------+----------+--------------+---------+-----------+
|Years.| Ores. | Metal. | Value of Ore.| Metal. | Average |
| | | | | | Standard. |
+------+---------+----------+--------------+---------+-----------+
| | | | | _Per_ | _Price_ |
| |_Tons of_|_Tons._ | | _Cent._ | _per Ton._|
| |_21 Cwts_| _Cwt._| _£ s. d._|_of Ore._| _£ s. d._|
| 1800 | 55,981 | 5187 0 |550,925 0 0 | 9-1/4 | 133 3 6 |
| 1801 | 56,611 | 5268 0 |476,313 0 0 | 9-1/4 | 117 8 0 |
| 1802 | 53,937 | 5228 15 |445,094 0 0 | 9-5/8 | 110 18 0 |
| 1804 | 64,637 | 5374 18 |507,840 11 0 | 8-3/8 | 136 5 0 |
| 1806 | 79,269 | 6863 10 |730,845 6 0 | 8-5/8 | 138 5 0 |
| 1808 | 67,867 | 6795 13 |495,303 10 0 | 10 | 100 7 0 |
| 1810 | 66,048 | 5682 19 |570,035 8 0 | 8-1/2 | 132 5 0 |
| 1812 | 71,547 | 6720 7 |549,665 6 0 | 9-3/8 | 111 0 0 |
| 1814 | 74,322 | 6369 13 |627,501 10 0 | 8-1/2 | 130 12 0 |
| 1816 | 77,334 | 6697 4 |447,959 17 0 | 8-5/8 | 98 13 0 |
| 1818 | 86,174 | 6849 7 |686,005 4 0 | 7-7/8 | 134 15 0 |
| 1820 | 91,473 | 7508 0 |602,441 12 0 | 8-1/8 | 113 15 0 |
| 1822 | 104,523 | 9140 8 |663,085 13 0 | 8-3/4 | 104 0 0 |
| 1824 | 99,700 | 7823 15 |587,178 0 0 | 7-7/8 | 110 0 0 |
| 1826 | 117,308 | 9026 12 |788,971 15 0 | 7-5/8 | 123 3 0 |
| 1828 | 130,366 | 9921 1 |756,174 16 0 | 7-5/8 | 112 7 0 |
| 1829 | 124,502 | 9656 10 |717,334 0 0 | 7-3/4 | 109 14 0 |
| 1830 | 143,296 |11,224 19 |887,900 0 0 | 7-3/4 | 114 4 0 |
| 1834 |}150,617 |12,271 14 |893,402 15 0 | 8-1/8 | 106 11 0 |
| 1835 |} | | | | |
+------+---------+----------+--------------+---------+-----------+

Produce of Copper Mines in Cornwall, (on the authority of John Taylor, Esq. F.R.S.)

+------+-------+-------+--------------+----------+---------+
|Years.| Ore. |Metal. | Value. | Produce. |Standard.|
+------+-------+-------+--------------+----------+---------+
| |_Tons._|_Tons._| _£. s. d._|_Per Cwt._| |
| 1831 |144,402|12,044 |806,090 15 6 | 8-1/4 | 100 |
| 1832 |137,357|11,948 |825,612 6 0 | 8-5/8 | 100 |
| 1833 |138,300|11,191 |858,708 10 0 | 8-1/8 | 111 |
| 1834 |143,296|11,226 |887,902 0 0 | 7-3/4 | 114 |
| 1835 |150,617|12,270 |893,402 14 0 | 8-1/8 | 106 |
| 1836 |140,981|11,647 |957,752 8 6 | 8-1/4 | 115 |
| 1837 |140,753|10,832 |908,613 15 0 | 7-5/8 | 120 |
+------+-------+-------+--------------+----------+---------+

An account of the quantities of Foreign wrought and unwrought Copper, and Copper Ore imported and exported, and of British wrought and unwrought Copper exported from the United Kingdom; together with the quantities and value of Copper Ore smelted in Cornwall and Swansea, and the quantity of Copper produced in those places; and in the county of Devon; together with the market prices of sheet and cake Copper, in the year ending 5th January, 1835.

+---------------------------------------------+-------+--------------+
| |Quanti-| Value. |
| | ty. | |
+---------------------------------------------+-------+--------------+
|Foreign Copper imported:-- | | _£ s. d._|
| Unwrought in bricks or pigs, rose and cast | | |
| copper _Cwts._ | 5,389| |
| Part wrought, viz., bars, rods, or ingots, | | |
| hammered or raised | 1,968| |
| Wrought plates and coin | 2| |
| -- old for re-manufacture | 493| |
| Copper ore Foreign |278,900| |
| Manufactures of copper, entered by weight | 650| |
| -- entered at value | -- | 5,353 0 0 |
|Foreign Copper exported, viz.:-- | | |
| Unwrought, in bricks and pigs, rose and | | |
| cast copper _Cwts._ | 6,898| |
| Part wrought, viz., bars, rods, or ingots, | | |
| hammered or raised | 2,013| |
| Old, fit only for re-manufacture | 265| |
| Smelted in the United Kingdom from foreign | | |
| ore | 55,456| |
| Manufactures of copper, entered by weight | 650| |
| -- entered at value | -- | 112 0 0 |
| | | |
| BRITISH COPPER. | | |
|Exported, unwrought, in bricks and pigs | | |
| _Cwts._ | 63,252| |
| -- wrought sheets, nails, &c. |103,433| |
| -- wire | 56| |
| -- of other sorts | 15,197| |
| -- Total of British copper exported |182,225| |
|Ores sold in Cornwall:-- | | |
| Quantity of ore _Tons_ |150,617| |
| Value of ditto | -- |893,403 0 0 |
| Quantity of metal _Tons_ | 12,270| |
| Standard | -- | 106 11 0 |
| Produce per cent. | 8-1/2| |
|Ores sold, &c. in Swansea:-- | | |
| Quantity of ore _Tons_ | 28,746| |
| Value of ditto | -- |223,958 0 0 |
| Quantity of metal _Tons_ | 2,832| |
| Standard | -- | 101 18 0 |
| Produce per cent. | 9-7/8| |
|Copper sold in Devonshire { ore } _Tons_ |{ 5,114| |
| { metal } |{ 455| |
|Total quantity of copper raised in the } | | |
|United Kingdom, exclusive of Anglesea and } | | |
|Staffordshire, and deducting 1083 tons of } | | |
|metal, value 88,207_l._, the produce of } | | |
|4985 tons of foreign ore sold at Swansea, } |-------| |
|included above. } | 14,474| |
+---------------------------------------------+-------+--------------+

COPPERAS. (_Couperose verte_, Fr.; _Eisenvitriol_, Germ.) Sulphate of iron.

CORAL, (_Corail_, Fr.; _Koralle_, Germ.) is a calcareous substance, formed by a species of sea polypus, which constructs in concert immense ramified habitations, consisting of an assemblage of small cells, each the abode of an animal. The coral is therefore a real polypary, which resembles a tree stripped of its leaves. It has no roots, but a foot not unlike a hemispherical skull-cap, which applies closely to every point of the surface upon which it stands, and is therefore difficult to detach. It merely serves as a basis or support to the coral, but contributes in no manner to its growth, like the root of an ordinary tree; for detached pieces have been often found at the bottom of the sea in a state of increase and reproduction. From the above base a stem usually single proceeds, which seldom surpasses an inch in diameter, and from it a small number of branches ramify in very irregular directions, which are studded over with cells, each containing an insect. The polypi, when they extend their arms, feelers, or _tentacula_, resemble flowers, whence, as well as from the form of the coral, they were classed among vegetable productions. They are now styled zoophytes by the writers upon Natural History.

The finest coral is found in the Mediterranean. It is fished for upon the coasts of Provence, and constitutes a considerable branch of trade at Marseilles. The coral is attached to the submarine rocks, as a tree is by its roots, but the branches, instead of growing upwards, shoot downwards towards the bottom of the sea; a conformation favourable to breaking them off and bringing them up. For this kind of fishing, eight men, who are excellent divers, equip a felucca or small boat, called commonly a coralline. They carry with them a large wooden cross, with strong, equal, and long arms, each bearing a stout bag-net. They attach a strong rope to the middle of the cross, and let it down horizontally into the sea, having loaded its centre with a weight sufficient to sink it. The diver follows the cross, pushes one arm of it after another into the hollows of the rocks, so as to entangle the coral in the nets. Then his comrades in the boat pull up the cross and its accompaniments.

Coral fishing is nearly as dangerous as pearl fishing, on account of the number of sharks which frequent the seas where it is carried on. One would think the diving-bell in its now very practicable state might be employed with great advantage for both purposes.

Coral is mostly of a fine red colour, but occasionally it is flesh-coloured, yellow, or white. The red is preferred for making necklaces, crosses, and other female ornaments. It is worked up like precious stones. See LAPIDARY.

CORK, (_Liége_, Fr.; _Kork_, Germ.) is the bark of the _quercus liber_, Linn., a species of oak-tree, which grows abundantly in the southern provinces of France, Italy, and Spain. The bark is taken off by making coronal incisions above and below the portions to be removed; vertical incisions are then made from one of these circles to another, whereby the bark may be easily detached. It is steeped in water to soften it, in order to be flattened by pressure under heavy stones, and next dried at a fire which blackens its surface. The cakes are bound up in bales and sent into the market.

There are two sorts of cork, the white and the black; the former grows in France and the latter in Spain. The cakes of the white are usually more beautiful, more smooth, lighter, freer from knots and cracks, of a finer grain, of a yellowish gray colour on both sides, and cut more smoothly than the black. When this cork is burned in close vessels it forms the pigment called _Spanish black_.

This substance is employed to fabricate not only bottle corks, but small architectural and geognostic models, which are very convenient from their lightness and solidity.

The cork-cutters divide the boards of cork first into narrow fillets, which they afterwards subdivide into short parallelopipeds, and then round these into the proper conical or cylindrical shape. The bench before which they work is a square table, where 4 workmen are seated, one at every side, the table being furnished with a ledge to prevent the corks from falling over. The cork-cutter’s knife is a broad blade, very thin, and fine edged. It is whetted from time to time upon a fine-grained dry whetstone. The workman ought not to draw his knife edge over the cork, for he would thus make misses, and might cut himself, but rather the cork over the knife edge. He should seize the knife with his left hand, rest the back of it upon the edge of the table; into one of the notches made to prevent it from slipping, and merely turns its edge sometimes upright and sometimes to one side. Then holding the squared piece of cork by its two ends, between his finger and his thumb, he presents it in the direction of its length to the edge; the cork is now smoothly cut into a rounded form by being dexterously turned in the hand. He next cuts off the two ends, when the cork is finished and thrown into the proper basket alongside, to be afterwards sorted by women or boys.

Of late years a much thicker kind of cork boards have been imported from Catalonia, from which longer and better corks may be made. In the art of cork-cutting the French surpass the English, as any one may convince himself by comparing the corks of their champagne bottles with those made in this country.

Cork, on account of its buoyancy in water, is extensively employed for making floats to fishermen’s nets, and in the construction of life-boats. Its impermeability to water has led to its employment for inner soles to shoes.

When cork is rasped into powder, and subjected to chemical solvents, such as alcohol, &c., it leaves 70 per cent. of an insoluble substance, called _suberine_. When it is treated with nitric acid, it yields the following remarkable products:--White fibrous matter 0·18, resin 14·72, oxalic acid 16·00, suberic acid (peculiar acid of cork) 14·4 in 100 parts.

_Machine cork-cutting._--A patent was obtained some years ago by Sarah Thomson for this purpose. The cutting of the cork into slips is effected by fixing it upon the sliding bed of an engine, and bringing it, by a progressive motion, under the action of a circular knife, by which it is cut into slips of equal widths. The nature or construction of a machine to be used for this purpose may be easily conceived, as it possesses no new mechanical feature, except in its application to cutting cork. The motion communicated to the knife by hand, steam, horse, or other power, moves at the same time the bed also, which carries the cork to be cut.

The second part of the invention, viz. that for separating the cork into square pieces, after it has been cut in slips as above, is effected by a moving bed as before, upon which the slips are to be placed and submitted to the action of a cutting lever, which may be regulated to chop the cork into pieces of any given length.

The third part of the invention, viz., that for rounding or finishing the corks, consists of an engine to which is attached a circular knife that turns vertically, and a carriage or frame upon its side that revolves upon an axle horizontally.

This carriage or frame contains several pairs of clamps, intended respectively to hold a piece of the square cut cork by pressing it at the ends, and carrying it lengthways perpendicularly; which clamps are contrived to have a spindle motion, by means of a pinion at the lower end of their axles, working into a spur-wheel.

The machinery, thus arranged, is put in motion by means of bands and drum-wheels, or any other contrivance which may be found most eligible; and at the same time that the circular knife revolves vertically, the frame containing the clamps with the pieces of cork, turns horizontally, bringing the corks, one by one, up to the edge of the knife, when, to render each piece of cork cylindrical, the clamps, as above described, revolve upon their axes, independently of their carriage, by which means the whole circumference of the cork is brought under the action of the knife, the superfluous parts are uniformly pared off, and the cork finished smooth and cylindrical.

CORROSIVE SUBLIMATE; bichloride of mercury.

CORUNDUM; or _Telesie_; a very hard genus of aluminous minerals, to which the gems, sapphire, ruby, salamstein, and adamantine spar belong.

COTTON DYEING. (_Teinture de Coton_, Fr.; _Baumwollenfärberei_, Germ.) Cotton and linen yarns and cloths have nearly the same affinity for dyes, and may therefore with propriety be treated, in this respect, together. After they have acquired the proper degree of whiteness (see BLEACHING) they are still unfit to receive and retain the dyes in a permanent manner. It is necessary, before dipping them into the dye-bath, to give them a tendency to condense the colouring particles within their cavities or pores, and to communicate such chemical properties as will fix these particles so that they will not separate, to whatever ordinary trial they may be subjected. All the colours which it would be desirable to transfer to these stuffs unfortunately do not possess this permanence. Men of science engaged in this important art have constantly aimed at the discovery of some new processes which may transfer into the class of fast colours those dyes which are at present more or less fugitive. Almost all the goods manufactured of cotton, flax, or hemp, are intended to be washed, and ought, therefore, to be so dyed as to resist the alkaline and soapy solutions commonly used in the laundry. Vitalis distinguished dyed cottons into three classes; 1. the _fugitive_, or fancy-coloured (_petit teint_), which change their hue or are destroyed by one or two boils with soap; 2. those which resist five or six careful washings with soap, are _good_ dyes, (_bon teint_); and those which were still more durable, such as Turkey reds, may be called _fast_ colours (_grand teint_). The colours of Brazil wood, logwood, annotto, safflower, &c., are _fugitive_; those made with madder without an oily base, are _good_; and those of madder with an oily mordant, are _fast_. It is, however, possible to point out certain processes for giving these different orders of dyes a greater degree of fixity.

I shall describe, in the five following paragraphs, the operations conducive to the fixation of colours upon cotton and linen.

1. _Galling._ Either gall nuts alone, or sumach alone, or these two substances united, are employed to give to cotton the fast dye preparation. 2 or 3 ounces of galls for every pound of cotton, being coarsely pounded, are to be put into a copper containing about 30 gallons of water for every 100 pounds of cotton, and the bath is to be boiled till the bits of galls feel pasty between the fingers. The fire being withdrawn, when the bath becomes moderately cool, it is passed through a hair-cloth sieve. If during this operation the liquor should become cold, it must be made once more as hot as the hand can bear. A portion of it is now transferred into another vessel, called a _back_, in which the cotton is worked till it be well penetrated with the decoction. It is then taken out, wrung at the peg or squeezed in a press, and straightway hung up in the drying house. Some more of the fresh decoction being added to the partially exhausted liquor in the back, the process is resumed upon fresh goods.

The manipulation is the same with sumach, but the bath is somewhat differently made; because the quantity of sumach must be double that of galls, and must be merely infused in very hot water, without boiling. When galls and sumach are both prescribed, their baths should be separately made and mixed together.

2. _Aluming._ Alum is a salt which serves to prepare cotton for receiving an indefinite variety of dyes. Its bath is made as follows: For 100 pounds of scoured cotton, about 30 gallons of water being put into the copper, are heated to about 122° F., when 4 ounces of alum, coarsely pounded, are thrown in for every pound of cotton, and instantly dissolved. Whenever the heat of the bath has fallen to about 98° F., the cotton is well worked in it, in order that the solution may thoroughly penetrate all its pores. It is then taken out, wrung at the peg or squeezed in the press, and dried in the shade. The solution of alum is of such constant employment in this kind of dyeing, that it should be made in large quantities at a time, kept in the alum tun, where it can suffer no deterioration, and drawn off by a spigot or stop-cock as wanted.

There are certain colours which require alum to be deprived of a portion of its acid excess, as a supersalt; which may be done by putting 1 ounce of crystals of soda into the tun for every pound of alum. But so much soda should never be used as to cause any permanent precipitation of alumina. When thus prepared, it is called _saturated alum_, though it is by no means neutral to litmus paper; but it crystallizes differently from ordinary alum.

Cotton does not take up at the first aluming a sufficient quantity of alum; but it must receive a second, or even a third immersion. In every case the stuff should be thoroughly dried, with an interval of one or two days between each application; and it may even be left for 10 or 12 hours moist with the alum bath before being hung in the air. When the cotton is finally dry, it must be washed before being plunged into the dye bath; otherwise, the portion of alum, not intimately combined with the cotton, but adhering externally to its filaments, would come off by the heat, mix with the bath, alter the colour by dissolving in it, and throw it down to the bottom of the copper, in the form of a lake, to the great loss of the dyer. Madder reds, weld yellows, and some other colours, are more brilliant and faster when acetate of alumina, prepared with acetate of lead, alum, and a little potash, is used, than even saturated alum. This mordant is employed cold, and at 4° Baumé.

3. _Mordants._ See this article in its alphabetical place.

4. _Dye baths_, are distinguished into two classes; the colouring bath, and the dyeing bath. The former serves to extract the colouring matters of the different substances, with the exception of madder, which is always used in substance, and never as an extract, infusion, or decoction. In all these cases, when the colour is extracted, that is, when the dye bath is completed by the degree of heat suited to each substance, it is then allowed to cool down a certain way, and the cotton is worked or winced through it, to get the wished-for tint. This is what is called the dye bath. Several colouring baths are made in the cold; and they serve to dye also in the cold; but the greater part require a heat of 90° or 100° to facilitate the penetration of the stuffs by the colouring particles. The description of the several dye baths is given under the individual dyes.

5. _Of the washing after the dyeing._--The washing of the cottons after they have received the dyes, is one of the most important operations in the business. If it is not carefully performed, the excess of colour not combined with the fibres, is apt to stain whatever it touches. This inconvenience would be of little consequence, if the friction carried off the colour equally from all the points; but it does not do so, and hence the surface appears mottled. A well-planned dye house should be an oblong gallery, with a stream of water flowing along in an open conduit in the middle line, a series of dash wheels arranged against the wall, at one side, and of dyeing coppers, furnished with self-acting winces or reels, against the other. In such a gallery, the washing may be done either by hand, by the rinsing machine, or by the dash wheel, according to the quality of the dye, and the texture of the stuffs. And they may be stripped of the water either by the jack and pin, by the squeezing roller, or by the press. Wooden pins are placed in some dye-houses on each side of the wash cistern or pool. They are somewhat conical, 1-1/2 foot high, 3-1/2 inches in diameter at the base, 1-1/2 at the top, are fixed firmly upright, and at a level of about 3 feet above the bottom of the cistern, so as to be handy for the workmen. See BRAZIL WOOD, FUSTIC, MADDER, BLACK DYE, BROWN DYE, &c., as also BLEACHING, BRAN, CALICO PRINTING, DUNGING, DYEING, &c.

COTTON MANUFACTURE. (_Filature de Coton_, Fr.; _Baumwollespinnerei_, Germ.) Cotton is a filamentous down, which invests the seeds of the plant called _gossypium_ by Linnæus, and placed by him in the class _monadelphia_ and order _monandria_, but belonging to the natural family of _malvaceæ_. It has a cup-shaped calyx, obtusely five-toothed, inclosed in a three-cleft exterior calyx; the leaflets are united at their base, of a heart shape and toothed; stigmas three to five; capsule three to five celled and many-seeded; seeds bearing a downy wool. Thirteen species are described by Decandolle, but their characters are very uncertain, and no botanist can assign to a definite species of the plant, the very dissimilar staples of the cotton filaments found in commerce. The leaves are generally palmate and hairy; and the blossoms are large, and of a beautiful yellow. The _gossypium religiosum_ of Tranquebar has white blossoms in some of its varieties, to which, probably, the white cotton of Rome, cultivated in the Jardin des Plantes at Paris, belongs. The filaments differ in length, flexibility, tenacity, and thickness, in different cottons, whence the great differences of their value to the cotton-spinner, as the prices current in the market show. Thus, at Liverpool, on the 1st of December, 1835, the following values were assigned to the following cottons:--

_s._ _d._ _s._ _d._
Sea-island 1 6 to 2 6
Demerara and Berbice 0 9 1 0
Pernambuco 0 10-3/4 1 1-1/2
Egyptian 0 11-1/2 1 2-1/2
New Orleans 0 7-1/8 1 0
Bahia 0 8-1/4 0 10
Upland Georgia 0 7-1/8 0 11-1/2
West Indian 0 7-3/4 0 9
Surat 0 6-1/8 0 8
Madras 0 6-1/2 0 8
Bengal 0 5-1/4 0 6-1/2

But it is to be observed, that there are varieties of the Sea-island Georgian cotton, so highly prized by the spinner of fine yarn, as to fetch 3_s._, 4_s._, or even 5_s._ per pound.

The filaments of cotton, when examined with a good microscope, are seen to be more or less ribbon-like, and twisted; having a breadth varying from 1/800 of an inch in the strongest Smyrna or candle-wick cotton of the Levant, to 1/2500 of an inch in the finest Sea-island.

The main distinction between cottons in the pod, is that of the black seeded, and the green seeded; for the former part with their downy wool very readily to a pair of simple rollers, made to revolve nearly in contact, by the power of the human arm; while the latter retain the wool with much force, and require to be ginned, as the operation is called, by a powerful revolving circular saw-mechanism, usually driven by horse or water power. After the cotton wool is thus separated from the seeds, it is packed in large canvas bags, commonly with the aid of a screw or hydraulic press, into a very dense bale, for the convenience of transport. Each of the American bags contains about 340 lbs. of cotton wool. When this cotton is delivered to the manufacturer, it is so foul and flocky, that he must clean and disentangle it with the utmost care, before he can subject it to the carding operation.

_Fig._ 317. A B, is a roller, about 9 inches in diameter, which revolves in the direction of the arrow. This cylinder consists of a parallel series of oblique pointed circular saws made fast to one axis, and parted from each other by wooden rings nearly one inch and a half in thickness. Above the cylinder is a kind of hopper E F, into which ginner throws the seed cotton, which falls upon a grating, up though which small segments of the saw-teeth project, so as to lay hold of the fibres in their revolution, and pull them through, while the seeds being thus separated, roll down the slope of the grid, to be discharged from the spout I K. M is a cylindrical brush placed below the grating, which revolves against the saw teeth, so as to clear them of the adhering cotton filaments.

The _willow_, which was originally a cylindrical willow basket, whence its name, but is now a box made of wood, with revolving iron spikes, is the first apparatus to which cotton wool is exposed, after it has been opened up, picked, and sorted by hand or a rake, in what is called a _bing_. The willow exercises a winnowing action, loosens the large flocks, and shakes out much of the dirt contained in them. The frame of the willow is about 2 feet wide, and turns with its spikes at the rapid rate of 600 revolutions per minute, whereby it tosses the cotton about with great violence. The heavy impurities fall down through the grid bottom. It is exposed, however, for only a few minutes to the action of this machine. For factories which work up chiefly the coarser and fouler cottons of India, and Upland Georgia, the conical self-acting willow, as constructed by Mr. Lillie at Manchester, is much employed. In it, the cotton is put in at the narrow end of the truncated cone, which, being spiked, and revolving rapidly within a nearly concentric case upon a horizontal axis, wafts it on towards the wide end, while its impurities are partly shaken out through the grid or perforated bottom, and partly sucked up through revolving squirrel wire cages, by the centrifugal action of a fan. This is a powerful automatic engine, deserving the study of the curious, and is as safe as it is powerful. The cone of this huge machine makes from 400 to 600 turns per minute, and will clean 7200 pounds, or 24 bags, in a day.

After shaking out the grosser impurities by the willow, the cotton spinner proceeds to separate each individual filament of cotton wool from its fellow, so as to prepare it for carding, and to free it from every particle of foreign matter, whether lighter or heavier than itself. This second operation is performed by what are called batting (_beating_), scutching, and blowing machines, which are all now much the same, whatever difference of signification the name may have. Indeed, each machine not only beats, scutches, but blows. _Fig._ 318. exhibits a longitudinal section of a good blowing engine of modern construction. The machine is about 18 or 19 feet long, and three feet across within the case. The whole frame is made of cast-iron, lined with boards, forming a close box, which has merely openings for introducing the raw cotton wool, for taking out the cleansed wool, and removing the dust as it collects at the bottom. These doors are shut during the operation of the machine, but may be opened at pleasure, to allow the interior to be inspected and repaired.

The introduction of the cotton is effected by means of an endless cloth or double apron, which moves in the direction of the arrow _a a_, at the left end of the figure, by passing round the continually revolving rollers at _b_ and _c_. The two rollers at _e_, being the ones which immediately introduce the cotton into the jaws, as it were, of the machine, are called the feed rollers. The batting arm, or revolving diameter, _f e_, turns in the direction of the arrow, and strikes the flocks violently as they enter, so as to throw down any heavy particles upon the iron grating or grid at _n_, while the light cotton filaments are wafted onwards with the wind, from the rotation of the scutcher in the direction of arrow _a´_, along the second travelling apron, upon which the squirrel cage cylinder presses, and applies the cotton in the form of a lap. Above the cylindric cage _h_, which turns in the direction of its arrow, there is a pipe _k_, the continuation of the case _i_. This pipe, though broken off in the figure, communicates by a branch pipe with an air-sucking fan ventilator, not seen in this figure, but explained under FOUNDRY. The cage _h_, by its rotation, presses down, as we have said, the half-cleaned cotton upon the cloth _a´_, which carries it forward to the second scutcher _f´_, by the second set of feed rollers _e´_. The second scutcher throws down the heavy dust upon the second grid _n´_, through which it falls upon the bottom of the case. The first scutcher makes about 1280 strokes of each of its two arms in a minute; the second 1300. The feed rollers for each are fluted. The feed cloth is either sustained by a board, or is made of parallel spars of wood, to secure it against bagging, which would render the delivery of the cotton irregular. The feed rollers make 8 turns in the minute, and as their diameter is 1-1/2 inches, they will introduce 8 times their circumference, or 37·7 inches of the cotton spread upon the apron in that time. Upon every 12th part of an inch of the cotton, therefore, nearly 3 blows of the scutcher arm will be applied. The second feed rollers move relatively with more slowness, so that for every 2·4 blows of the scutcher, only one twelfth of an inch of cotton wool is presented.

The fan is inclosed in a cylindrical case. The wings or vanes revolve from 120 to 150 times in the minute; and while they throw the air out with nearly this velocity at their excentric outlet in the circumference, they cause it to enter, with equal velocity, at the centre. With this centre the squirrel cage is connected by a pipe, as above stated. The sound filaments of the cotton are arrested by the sieve surface of the cylindric cage, and nothing but the broken fragments and the light dust can pass through.

The cotton wool in the blowing machine is wafted by the second scutcher into the space _x_, _w w_, provided with a fine grid bottom; or it is sometimes wound up there by rollers into a lap.

In _fig._ 318. an additional ventilator is introduced beneath at _m_, _o o_, to aid the action of the scutchers in blowing the cotton onwards into the oblong trough _a_. The outlet of that fan is at _t_; and it draws in the air at its axis _q_. _u_ and _v_, are two doors or lids for removing the cleaned cotton wool. This last fan is suppressed in many blowing machines, as the scutching arms supply a sufficient stream of air. The dotted lines show how the motion is transmitted from the first mover at _s_, to the various parts of the machine. 6´ 6´ represent the bands leading to the main shafting of the mill. A machine of this kind can clean fully 600 pounds of short-stapled cotton wool in a day, with the superintendence of one operative, usually a young woman, to distribute the cotton upon the first feed cloth.