752 GUM 



unonumerated,' which will evidently comprehend some guanos the remainder being 

 chiefly phosphates of lime : 



Value 



Tons 



From Germany 38,592 102,737 



France 13,905 >_>. 641 



Portugal, Azores, and Madeira 15,656 fil.198 



Spain 1,649 5,894 



United States of America . 35,446 88,811 



Dutch West India Islands . 3,131 12,080 



II ivti and St. Domingo . . 11,269 41,241 



British West India Islands . 8,305 33,173 



Other countries . . . 3,983 22,664 



Total . . . 131,936 420,739 



GUARANTN. In the preparation of caffeine from guarana, an alkaline com- 

 pound was obtained, to which this name was given. See CAFFEINE. 



GUAVA. This fruit is a native of the two Indies and the Brazils. There are two 

 well-known varieties, the Psidium pomiferum, or apple-fruited guava ; and the P. pyri- 

 ferum, the pear-fruited variety. The pulpy fruits of these trees make, with sugar, 

 excellent preserves, which are imported as Guava jelly. 



GUIGNET'S GREEN. A basic hydrate of chromium, used as a pigment. See 

 CHROMIUM. 



GUINEA CORN*. The grain of Holcus Sorghum. 



GUINEA PEPPER. Another name for the Grains of Paradise. 



GUIPURE. A lace made at Limerick by cutting out the pattern from cambric ; 

 the flowers and ornamental parts being formed of the cambric, and the open part of 

 stitches which resemble the antique lace. 



GUM (Gomme, Fr. ; Gummi, Pflanzenschleim, Ger.) is the name of a proximate 

 vegetable product, which forms with water a slimy solution, but is insoluble in 

 alcohol, ether, and oils. It is converted by strong sulphuric acid into oxalic and mucic 

 acids. 



There are six varieties of gum: 1, gum arabic; 2, gum Senegal; 3, gum of the 

 cherry and other stone-fruit trees ; 4, gum tragacanth ; 5, gum of Bassora ; 6, the 

 gum of seeds and roots. The first five spontaneously flow from the branches and 

 trunks of their trees, and sometimes from the fruits in the form of a mucilage which 

 dries and hardens in the air. The sixth kind is extracted by boiling water. In com- 

 merce, under the name of gum, very different substances are confounded ; thus wo 

 have gum elemi and gum copal, which are true resins ; and gum ammoniacum, which is 

 a gum resin ; and gum elastic (caoutchouc), which is a peculiar body, differing from 

 either. 



Gum arabic and gum Senegal consist almost wholly of the purest gum called 

 arabine by the French chemists ; our native fruit-trees contain some cerasine, along 

 with arabine ; the gum of Bassora and gum tragacanth consist of arabine and 

 bassorine. 



Gum arabic, flows from the Acacia ardbica, and the Acacia vera, which grow upon 

 the banks of the Nile and in Arabia. It occurs in commerce in the form of small 

 pieces, rounded upon one side and hollow upon the other. It is transparent, without 

 smell, brittle, easy to pulverise, sometimes colourless, sometimes with a yellow or 

 brownish tint. It may be bleached by exposure to the air and the sunbeams, at the 

 temperature of boiling water. Its specific gravity is 1'355. Moistened gum arabic 

 reddens litmus-paper, owing to the presence of a little supermalate of lime, which 

 may bo removed by boiling alcohol ; it shows also traces of the chlorides of 

 potassium and calcium, and the acetate of potash. 100 parts of good gum con- 

 tain 70'40 of arabine, 17'60 of water, with a few per cents, of saline and earthy 

 matters. Gum arabic is used in medicine, as also to give lustre to crapes and other 

 silk-stuffs. See ACACIA. 



Gum Senegal is collected by the negroes during the month of November, from the 

 Acacia Senegal, a tree 18 or 20 feet high. It comes to us in pieces about the size of a 

 partridge's egg, but sometimes larger, with a hollow centre. Its specific gravity is 

 1-436. It consists of 81'10 arabine ; 16'10 water ; and from 2 to 3 of saline matters. 

 The chemical proper! i s ;iml uses of this gum are the same as those of gum arabic. 

 It is much employed in calico-printing. 



Cherry-tree gum consists of 52 - 10 araliine ; 34'90 cerasine ; 12 water; and 1 saline 

 matter. It is used by hatters for smoothing the nap. 



