Ether , boiling hot, dissolves 39-17 per cent, of copal.
Essence (spirits) of turpentine does not dissolve any of the copal, but it penetratesand combines with it at a heat, of 212° Fahr.
The property of swelling, becoming viscid and elastic, which Berzelius assigns tocopal, belongs not to it, but to the American resin of courbaril, or the Occidentalanime ; and the property of dissolving entirely in ether belongs to the aromatic dam-mar, a friable and tender resin.
2. Resin of courbaril of Rio Janeiro, the English gum-anime, and the semi-hardcopal of the French . It is characterized by forming, in alcohol, a bulky, tenacious,elastic mass. It occurs in rounded tears, has a very pale, glassy aspect, transparentwithin, covered with a thin white powder, which becomes glutinous with alcohol.Another variety is soft, and dissolves, for the most part, in alcohol; and a third re-sembles the oriental copal so much as to indicate that they may both be produced fromthe same tree., 100 parts of the oriental and the occidental anime yield respectivelythe following residua:—
With alcohol. With ether. With essence.
Oriental - - - 65-71 60-83 111 .
■ Occidental - - - 43-53 27-50 75-76
The hard and soft copals possess the remarkable property in common of becomingsoluble in alcohol, after being oxygenated in the air.
3. Dammar puti, or dammar balu. —This resin, soft at first, becomes eventually
like amber, and as hard. It is little soluble in alcohol and ether, but more so inessence of turpentine. .
4. Aromatic dammar. —This resin occurs in large orbicular masses. It is pretty-soluble in alcohol. Only small samples have hitherto been obtained. Of 100 parts, ^are insoluble in alcohol, none in ether, and 93 in essence of turpentine. M. Guibourtthinks that this resin comes from the Molucca islands. Its ready solubility in alcohol,and great hardness, render it valuable for varnish-making.
5. Austral dammar. —This resin is the product of the Dammara-australis, one of thehighest trees in New Zealand , where it l's called Kaure or Kauri. It resembles elemiin some measure. It flows from the trunk and branches in the form of a resinousjuice called van, and gum-cowdee by the English settlers. The natives chew it con-tinually, and with the soot obtained from its combustion they make the indelible blacktatoo figures upon their faces. It comes home in lumps of considerable size. It pos-sesses a certain toughness, which makes it difficult to break or to pulverize. It takesfire at a candle-flame, and continues to burn by itself. It melts in water, heatedbelow the boiling point. Alcohol boiled with it, leaves 43-3 per cent, of insolublematter; ether leaves' 36-66; and essence of turpentine 80 percent. This resin, infact, resembles very closely the resin of courbaril.
6. Slightly aromatic dammar leaves, after alcohol, 37 per cent.; after ether, 17 percent.; and after essence, 87 per cent.
7. Tender and friable dammar selan.— This resin occurs in considerable quantity incommerce (at Paris ). It is in round or oblong tears, vitreous, nearly colorless andtransparent within, dull whitish on the surface. It exhales an agreeable odor ofolibanum, or mastic, when it is heated. It cractles with the heat of the hand likeroll-sulphur. It becomes fluid in boiling water, but brittle when cooled again. Itsparkles and burns at the flame of a candle; but this-being the effect of a volatile oil,the combustion soon ceases.
Resin soluble in cold alcohol - - - 75-28
Resin insoluble in boiling alcohol - 20-86
It dissolves readily and completely in cold essence of turpentine, and forms a goodvarnish. M. Guibourt refers the origin of this resin to the Dammara selanica ofRumphius Of the preceding resins, 100 parts have left respectively.
Alcohol of 0.830.
Essence.
Hard copal, or anime
- 65-71
60-83
Ill
Tender copal
. - 43-53
27-50
75-76
Dammar puti
—
—
—
Dammar aromatic
- 3.0
—
93
Dammar austral -
- 43-33
36-66.
80
Dammar slightly aromatic
- 37-00
17-00
87
Dammar friable
- 20-86
2-00
— •
RETORTS OF CLAY are now extensively used in gas-making, and they are wellhianufactured at Newcastle. See the article Gas.