760 SEPIA 



Dark Blue. 3 oz. Venetian turpentine, 7 oz. fine shellac, 1 oz. colophony, 1 oz. 

 mineral blue. 



Green. 2 oz. Venetian turpentine, 4 oz. shellac, 1^ oz. colophony, J oz. king's 

 yellow, ^ oz. mountain blue. 



Gold. 4 oz. Venetian turpentine, 8 oz. shellac, 14 sheets of genuine leaf-gold, oz. 

 bronze, oz. magnesia with oil of turpentine. 



SEA-WATER. The following has been given as the average composition of 

 sea-water in 100 parts: Chloride of sodium, 2 - 50 ; chloride of magnesium, 0'35 ; 

 sulphate of magnesia, 0'58 ; carbonates of lime and of magnesia, 0'02 ; sulphate of 

 lime, 0-01. 



Dr. John Davy informs us that carbonate of lime is chiefly found in sea-water 

 near the coast. Dr. George "Wilson proved the existence of fluorine in the waters of 

 the German Ocean, and Foret Lammr obtained it from sea-water collected near 

 Copenhagen ; Malaguti and Durdcher have detected silver in sea-salt, and Mr. Field 

 has shown that the copper sheathing of ships separates silver, in the process of time, 

 from the waters of the ocean. 



Lead and copper and some other metals have also been detected in sea-water, and 

 in the ashes of some marine plants. These metals are said to exist in the sea- 

 water in the form of chlorides, and to have been probably derived from the native 

 sulphides of the metals by the action of the chlorine in the water. 



SECRET AGE. A process in which mercury, or some of its salts, is employed to 

 impart to the fur of animals the property of felting, which they did not previously 

 possess. See FUR ; MERCURY. 



SEEDS imported in 1874: 



Value 

 Clover and Grass . . . 256,025 cwts. 588,768/. 



Cotton 190,549 tons 1,514,561Z. 



Flax and Linseed . . . 1,682,875 qrs. 4,678,750Z. 



Eape 289,781 686.719/. 



BEGGAR. See SAGGER ; POTTERY. 



SEXiENXTE. Hydrated sulphate of lime. See AIABASTEB ; GYPSUM. 



SELENIUM, from at\4\vt\, selene, ' the moon,' is a chemical element, discovered 

 by Berzelius in 1817. It occurs sparingly in combination with several metals, as 

 lead, cobalt, copper, and quicksilver, in the Hartz, at Tilkerode ; with copper and 

 silver (Eukairite) in Sweden, with tellurium and bismuth in Norway, with tellurium 

 and gold in Transylvania, in several copper and iron pyrites, and with sulphur in 

 the volcanic products of the Lipari Islands. Seleuium has been found likewise in .'i 

 red sediment which forms upon the bottoms of the lead-chambers in which oil of 

 vitriol has been made from a peculiar pyrites, or pyritous sulphur. The extraction 

 of selenium from that deposit is a very complex process. 



Selenium, after being fused and slowly cooled, appears of a bluish-grey colour, with 

 a glistening surface ; but it is a reddish-brown, and of metallic lustre when quickly 

 cooled. It is brittle, not very hard, and has little tendency to assume the crys- 

 talline state. Selenium is dark red in powder, and transparent, with a ruby cast, 

 in thin scales. Its specific gravity is 4'39. It softens at the temperature of 176 

 Fahr., is of a pasty consistency at 212, becomes liquid at a somewhat higher 

 heat, forming in close vessels dark yellow vapours, which condense into black drops ; 

 but in the air the fumes have a cinnabar-red colour. The atomic weight of selenium 

 is 39 - 7, and its symbol Se. See "Watts's ' Dictionary of Chemistry.' 



SELTZER-WATER. See SODA-WATER, and WATERS, MINERAL. 



SEMOITXiE. The name given in France to denote the large hard grains of wheat- 

 flour retained in the bolting machine after the fine flour has been passed through its 

 meshes. The best semoule is obtained from the wheat of the southern parts of 

 Europe. With the semoule the fine white Parisian bread called gruau is baked. 

 Skilful millers contrive to produce a great proportion of semoule from the large- 

 grained wheat of Naples and Odessa. 



Granular preparations of wheat deprived of bran are known in this country as 

 Semolina, Soujee, and Manna-croup. 



SENEGAL GUM. This gum is produced from the Acacia Senegal, a, tree or 

 shrub found in Arabia and the interior of Africa. See GUM. 



SEPIA is a pigment prepared from a black juice secreted by certain glands of the 

 cuttle-fish, which the animal ejects to darken the water when it is pursued. One part 

 of it is capable of making 1,000 parts of water nearly opaque. All tlio species of 

 this mollusc secrete the same juice ; but the Sepia officinalis, the S. loligo, and 

 the S. tunicata, are chiefly sought after for making the pigment. The first, which 

 occurs abundantly in the Mediterranean, affords most colour ; the sac containing 



