UTILIZATION OF SEAWEEDS IN THE UNITED STATES. 



17'. i 



alginate of calcium or aluminum being precipitated. With either salt the alginate is thrown down 

 instead of rising to the surface of the liquid, and the cakes are more compact and easily pressed. In 

 addition to the cheapness with which it can be procured in almost any quantity, as a by-product in 

 alkali works, now all thrown away, the calcium chloride lias the advantage of throwing down the 

 sulphates in the salts, and decomposing them into chlorides of potassium and sodium, which arc easilj 

 separated, and do not require the tedious and expensive processes necessary in the lixiyiation of kelp. 

 The same remark applies to aluminum chloride, which can he cheaply obtained by dissolving bauxite 

 in hydrochloric acid. Either salt can l>c decomposed by hydrochloric acid, and the calcium and 

 aluminum chlorides recovered; or the salts can be decomposed by sodium carbonate. The calcium 

 alginate, when dry, is very like hone, as the dry alginic acid is like horn. The aluminum alginate 

 is sol u hie in caustic soda, forming a neutral solution, and giving, on evaporation, a substance like algin, 

 but harder and making a stiffer finish ; it is also soluble in ammonia, the sail becoming an insoluble 

 varnish on evaporation. The alginates of copper (blue), nickel (green), cobalt (red), chromium 

 i green I, and zinc are all soluble in ammonia, and form beautiful 

 colored insoluble films on evaporation. So also do the alginates of 

 platinum, uranium ( yellow ), and cadmium. The latter is exceed- 

 ingly soluble in ammonia. The alginate of chromium is also 

 soluble in cold water, and it is deposited on boiling the solution, 

 becoming then insoluble. 



With bichrome, algin acts as gelatin, the mixture becoming 

 insoluble under the influence of light. The silver alginate dark- 

 ens very rapidly underexposure to light, and suggests applications 

 in photography. Algin forms a singular compound with shellac, 

 both being soluble in ammonia ; it is a tough sheet, which can be 

 rendered quite insoluble by passing it through an acid bath. 



Algin and its stills appear to have a wide range of 

 useful i less. Some of these are indicated by Stanford 

 (I. c). Thus, as a sizing for fabrics, algin supplies the 

 great desiderata of a soluble gum with marked elastic 

 and flexible properties, and of a soluble substitute for 

 albumen which can easily be rendered insoluble and 

 used as a mordant. As a stiffening and rilling agent, 

 algin has an advantage over starch, in that it tills the 

 cloth better, is tougher and more elastic, is transparent 

 when dry, and is not acted on by acids. It imparts to 

 fabrics a thick, elastic, clothy feeling, without the stiff- 

 ness caused by starch. An additional advantage, pos- 

 sessed by no other gum, is that algin becomes insoluble 

 in the presence of dilute acids; and, furthermore, no other gum has anything like the 

 viscosity of algin, hence it is the most economical for making solutions for sizing. 

 The alginate of aluminum in caustic soda makes a stiff dressing; in the crude 

 unbleached state it is a cheap dressing for dark goods, and in the colorless slate for 

 liner fabrics. A glossy, insoluble surface results from the use of ammoniated 

 alginate of aluminum. 



Sodium alginate has been used for fixing mordants, and is a substitute for the 

 various salts now used in precipitating mordants previous to the dyeing of cottons 

 and yarns. For resolving and preventing the incrustation of boilers, sodium alginate 

 has been pronounced by experts to be one of the best preparations, precipitating the 

 lime salts in a state in which they can readily be blown off. 



Sea lettuce | Viva latissima >. 



