605 



CAKAWAY, OIL OF, 



CARBAMIC ACID. 



606 



in much the same manner ; but it is not BO large, find its route, by the 

 head of the Red Sea and through a country where fierce Bedouin 

 Arabs are plentiful, and wells of water very scarce, is much more 

 dangerous. 



The Persian caravan to Mecca, which used to come by Bagdad 

 through Mesopotamia and Syria, and the Moggrebin (or Moorish) 

 caravan, which, starting from Marocco, used to travel all through 

 Northern Africa, have both become very irregular, though many 

 Persians, Moors, and negroes find their way to Jidda, the port of 

 Mecca, by sea. Considerable troops of Mohammedan Indians also visit 

 Mecca. The great Indian caravan, which started from Muscat and 

 travelled by Nejd to Mecca, has long been given up. 



When the caravans arrive at Mecca, bringing with them goods from 

 no many parts of the world, that city presents the appearance of a vast 

 fair. In former times there was a second great pilgrimage and fair at 

 Medina. This is frequently divided into two portions, the ' tayyarah,' 

 or flying caravan, and the ' rakb ;' but even in this each person only 

 carries his own saddle-bags. 



Besides these large annual caravans, others on a smaller scale are 

 constantly occurring in the East, where merchants and travellers going 

 the same road wait for one another until they can form a caravan, 

 when they generally appoint one of their voluntary association to regu- 

 late the order of march. A recent writer, visiting Ararat, says that in 

 the neighbourhood of that mountain he saw the halt of one of those 

 caravans which traverse Armenia in the way to and from Persia ; that 

 its encampment occupied several miles in extent, that nearly three 

 thousand horses were scattered over the plain, and that the carriers 

 and travellers amounted to seven or eight hundred. He adds, that the 

 horses were carefully tended, and that the evolutions of the train were 

 performed without noise and with much regularity. 



The cararan-taraie, or halting-places for the caravans, are generally 

 plain four-sided buildings, with an inner open court, around which 

 are one or two rows of totally unfurnished apartments for the use of 

 travellers, who are expected to bring with them all they need. They, 

 in fact, only afford some protection for the cattle and goods against 

 marauders, and usually furnish a supply of water. They are commonly 

 situated in the wildest and most desolate places, and the institution 

 and support of them is deemed highly meritorious by all devout 

 Mohammedans. 



But the caravan trade is not limited to Southern Asia. The great 

 trade between China and Russia is a caravan trade. The road runs 

 from Peking through the great wall to Chalgan, where the goods are 

 taken from horses and put upon camels, which are kept and let out 

 for this purpose by the Kalka-Mongols. From Chalgan the route lies 

 through part of the desert of Kobi to Kiachta, the great border-market 

 for the barter of Chinese and European articles : the journey is from 

 70 to 90 days. Other similar lines of route exist in Russia and the 

 countries to the east of the Caspian Sea. All the trade with the 

 interior of Africa is also carried on by means of caravans, though they 

 are there especially known as CAFFILAS. They are composed of camels 

 and asses ; and Captain R. F. Burton has given an account of them in 

 his ' First Footsteps in East Africa,' 1856 ; as also of those of Asia, in 

 his ' Pilgrimage to El Medinah and Meccah,' 1856. 



Among the knights of Malta, in whose history it is continually used, 

 the word caravan had a very different meaning. It signified a troop or 

 corps of knights appointed by the Order to serve in any garrison, and 

 also the crew or the cruize of any of their galleys against the Turks ; 

 for such cruizes were called caravans, and every knight was bound by 

 the laws of his society to make so many caramm, or, in other words, 

 so many sea-voyages. 



CAKAWAY, OIL OF. The essential oil of caraway is obtained by 

 distilling the crushed seeds of the C'arum Carui. About five per cent. 

 of the oil is obtained. At first the oil is of a pale yellow colour, but 

 it subsequently becomes brownish ; it possesses a penetrating aromatic 

 odour and taste, and an acid re-action. Its sp. gr. is '938, and it boils 

 at 401. It appears to contain two hydrocarbons, one analogous to 

 CTMEN, and the other to CUMINOL. Distilled with caustic potash it 

 yields caruen, or carvene (C IO H,), and the residue contains an acrid oil, 

 to which the name caruacrol, or careole (C V H M 0,), has been given. 



Oil of caraway is employed as a flavouring agent, and in medicine. 

 A v>lution of it in spirit is drunk in Germany, under the name of 

 KiiiHmdicatter. 



CARAWAYS, the ripe fruit of C'arum Carui, an umbelliferous, 

 European plant, of annual or biennial duration, with finely-divided 

 aromatic leaves, white small flowers, and a fusiform root, not unlike 

 that of a small parsnip. The seeds, as they are vulgarly called, are 

 the furrowed halves of the ripe fruit, have a peculiar aromatic flavour, 

 and are used as an agreeable carminative by confectioners ; the roots 

 themselves are eaten in the north of Europe. 



Caraways are used in medicine as a carminative, and more exten- 

 sively by the confectioners, and by the brewers' druggists to give 

 flavour to the beer. The chief English cultivation of the plant is in 

 Essex and Suffolk, upon old grass land broken up for the purpose. As 

 it is a biennial, it i generally sown with another plant of the same 

 tribe called coriander ; and sometimes a crop of teazles is raised on the 

 Mine land ; the three give a very valuable return during two or three 

 yean. 

 Arthur Young, in his ' Agricultural Survey of Essex,' describes this 



mode of cultivation minutely. Some old pasture laud is ploughed up 

 in spring ; if the soil is a strong rich clay so much the better. Ten 

 pounds of caraway seed, ten pounds of coriander, and twelve pounds 

 of teazle seed are sown together on the newly turned-up soil, and 

 harrowed in. As the plants appear they are carefully freed from all 

 weeds, by repeatedly hoeing the land. The coriander is fit to be cut 

 in July, and is threshed out on a cloth in the field. The produce is 

 sometimes twenty cwt., worth on an average 16s. per cwt. The next 

 year the caraway is reaped about the same time, and produces from 

 3 to 20 cwt., worth 30s. per cwt. In the autumn of the same year the 

 teazles are fit to be cut. The produce of these is very various ; some- 

 times worth \1l., at other times only a quarter of that amount. The 

 laud, which would have been too rich for corn when first broken 

 up, is now reduced to a moderate state of fertility. From this it is 

 evident that it is only under peculiar circumstances that this profitable 

 cultivation can be (tfopted. 



CARBAMIC ACID (C 2 H,N0 4 ). When dry carbonic acid gas (CO 2 ) 

 and dry ammoniacal gas (NH a ) are brought into contact, a white solid 

 substance results. This has been called anhydrous carbonate of 

 ammonia, but as it differs from that salt in all its more important 

 characters it is now always classed with the amidated acid compounds 

 produced by the re-action of dry ammoniacal gas on acid anhydrides, 

 and is called carbamate of ammonia. It may be viewed as carbamic 

 acid in which an equivalent of hydrogen is replaced by ammonium 

 (NH,). Thus 



NH 2 (CO) S ) NH,(CO).C 



HO j NH 4 C 



Carbamic acid. 



Carbamate of ammonia. 



Carbamic acid, it will be perceived, is derived from one equivalent 

 of dry ammoniacal gas and two equivalents of carbonic acid ; an 

 equivalent of hydrogen of the former and an equivalent of oxygen of 

 the latter uniting to form water. 



Carbamate of ammonia possesses a strong ammoniacal odour, is very 

 alkaline, and volatilises at 140 Fahr. Its vapour density is equal to 

 0'9. Anhydrous sulphuric acid converts it into sulphamate of ammonia, 

 with disengagement of carbonic acid. Heated with sulphurous acid 

 it gives an orange sublimate. Hydrochloric acid converts it, with the 

 aid of heat, into carbonic acid and chloride of ammonium. It is very 

 soluble in water, and is then rapidly converted into neutral carbonate 

 of ammonia. When, however, carbonic acid is passed into solution of 

 ammonia, carbonate of ammonia is not formed till after some time, or 

 when the liquid is boiled. It is important to bear this in mind in the 

 estimation of the carbonic acid in a mineral water, by means of an 

 ammoniacal solution of chloride of calcium, as otherwise an error may 

 occur. 



Carbamate of methyl (c 4 H 6 N0 4> or NHa ^ < H i } ) ( uretj '!/ lane )- 



One of the several methods of producing this substance is to pass 

 chloride of cyanogen into wood spirit containing a little water. When 

 the latter is saturated it has a strong acid re-action, much ammoniacal 

 salt is deposited, which should be removed and the liquid distilled. 

 When the temperature has risen to about 280 Fahr., the receiver 

 should be changed, and all that passes over between that degree and 

 about 360 Fahr. collected and set aside. After a day or two it deposits 

 crystals of carbamate of methyl, which after strong pressure are usually 

 quite pure. In this re-action other matters are produced, but the 

 principal decomposition is expressed in the following equation : 



2C 2 H 4 0, + C 2 N, Cl = C 4 H 5 NO 4 + C.,H 3 , Cl 



Methyl- Chloride Carbamate of Chloride of 

 alcohol, of cyanogen. methyl. methyl. 



Carbamate of methyl crystallises in elongated tabular plates. They 

 are not deliquescent. Melting-point, when perfectly dry, 125-0 3 Fahr.; 

 boiling-point, 350 Fahr. ; vapour density equal to 2'02 : very soluble 

 in water and alcohol, less so in ether. Dilute sulphuric acid decom- 

 poses it into carbonic acid, methylic alcohol, and sulphate of ammonia ; 

 potash does the same, strong sulphuric acid blackens it, sulplmrous 

 acid and an inflammable gas being evolved. 



Carbamate of ethyl C H,NO,, or ^'^g 3 0} (>"' et ^ ii e)- Ordi- 

 nary spirit of wine is saturated with chloride of cyanogen, and the 

 mixture heated over a water-bath in a flask with a long neck. Among 

 other re-actions the following takes place : 



2C 4 H O, + CjN, Cl = C,H,NO, + C 4 H b , Cl 



Ethyl, 

 alcohol. 



Chloride of Carbamate 

 cyanogen. of ethyl. 



Chloride of 

 ethyl. 



The resulting liquid poured off from an ammoniacal salt that deposits 

 is submitted to distillation; ether, alcohol, and carbonic ether pass 

 over, and finally leaf-like crystals of carbamate of ethyl are obtained. 



This substance may also be produced by the re-action of ammonia 

 on the carbonate or chlorocarbonate of ethyl. It is white, fusible at 

 212 Fahr., and distils when quite dry at about 356 Fahr., but if at 

 all moist, decomposition occurs, and torrents of ammoniacal gas are 



