October r, 1884.J THE TROPTCAL AGRICULTURIST 



319 



Laminar ia Bulbosa. 

 Fucus vesiculous. 



Laminaria Stenophylla. 

 Stem. Frond. 



Water ... 345 40'02 43-28 



Alginic acid... 257 24'06 17-95 



Cellulose ... 11-27 1506 1115 



FALKLAND ISLANDS GIANT ALGjfc. 



Nos 1 2 3 4 



Alginic acid ... 1121 1009 5-5G 744 

 Cellulose ... 8-13 725 350 12-95 



The three gelatiuous algre, already referred to, 

 uo algin. 



The cellulose in the tangle is higher than in any other 

 weed, the outside of the stem being rather fibrous. I 

 append also analyses of the ash of three varieties of 

 cellulose dry, unbleached to show the trace of iodine still 

 retained :- 



4010 



12-22 



5 

 3-34 

 9-68 

 contain 



The new process may be tabulated as follows: — 



Per cent. 

 Extracted by water — 



Salts 20 



Sugar, mucilage, &c. ... ... 10 



Extracted by sodium carbonate- 

 Algin 

 Dextrine, &c. 



Cellulose 

 Moisture 



30 



20 



10 



30 

 10 

 30 



100 



Of these, I have accounted for the salt, the algin, and 

 the cellulose, leaving the mucilage, dextrine, and sugar for 

 further investigation. 



It is uot necessary to extract the salts first with water, 

 it comes to the same thing to act on the seaweed at once 

 with soda ash, and to recover the salts by evaporation of 

 the solution, after the alginic acid has been precipitated. 

 In this case chloride of calcium or of aluminum may 

 be employed, the alginate of calcium or aluminium 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 additon 

 to the cheapness with which it can be procured in almost 

 any quantity, as a bye-product in alkali works, now all 

 thrown away, the calcium chloride has the advantage of 

 throwing down the sulphates in the salts, and decomposing 

 them into chlorides, so that the salts consist of chlorides 

 of potassium and sodium, which are easily separated, and 

 do not require the tedious and expensive processes necessary 

 iu the lixiviation of kelp. The same remark applies to 

 aluminum chloride, which can be cheaply obtained by 

 dissolving bauxite in hydrochloric acid. Either salt can be 

 decomposed by hydrochloric acid, and the calcium or 

 aluminum chlorides recovered ; or the salts can be decom- 

 posed by sodium carbonate. The calcium alginate, when 

 dry, is very like bone, as the dry alginic acid is like horn. 

 The aluminum alginate is soluble in caustic soda, forming 

 a neutral solution, and giving, ou evaporation, a substance 

 like algin, but harder and making ;i stiffer finish; it is 

 also soluble iu ammonia, the salt becoming an insoluble 

 varnish on evaporation. The alginates of copper (blue), 

 nickel (green), cobalt (red), chromium (green) and zinc, 

 are all soluble iu ammonia, and form beautiful coloured 

 insoluble films ou evaporation. So also do the alginate's 

 of platinum, uranium (yellow,, and cadmium. The latter 

 is exceedingly soluble in ammonia. The alginate of chro- 

 mium is also soluble iu cold water, and it is deposited 

 on boiling the solution, becoming then insoluble. 



With bichrome, algin acts as gelatine, the mixture be- 

 coming iusoluble under the influence of light. The silver 

 alginate darkens very rapidly under exposure to light, and 

 suggests applications in photography. Algin forms a sin- 

 gular compound with shellac, both being soluble in am- 



monia ; it is a tough sheet, which can be rendered quite 

 insoluble by passing it through an acid bath. 



COMMEKCiaL APPLICATION OF ALGIN OE SODIUM ALGINATE. 



For Sizing Fabrics. — A soluble gum of considerable 

 elasticity and flexibility is a greater desideratum; so also 

 is a soluble substitute for albumen, which can' be easily 

 rendered insoluble and used as a mordant. As a fiuish, 

 algin has the advantage over starch, that it fills the 

 cloth better, that it is tougher and more elastic, that it 

 is transparent when dry, and that it is not acted upon 

 by acids. It imparts to the goods a thick clothy elastic 

 feeling, without the stiffness imparted by starch. It has 

 the additional advantage which uo other gum possesses, 

 of becoming insoluble in the presence of a dilute acid, 

 which decomposes starch or dextrine. No other gum has 

 anything like the viscosity in solution, and therefore none 

 will go as far in making up the solution or cover such a 

 large surface. Lime-water, salts of calcium, barium, and 

 various metallic salts can be employed for rendering the 

 coating insoluble. If greater stiffness be required, the 

 algin can be mixed with gum arable, starch, dextrine, 

 gelatine, albumen, or glue, iu any proportion. 



The alginate of alumina in caustic soda is a stiff dress- 

 ing, and iu the crude, unbleached state, will be a cheap 

 dressing for dark materials; and in the colourless state for 

 finer fabrics. The animoniated alginate of alumina can 

 be used to give a glossy surface, which is quite insoluble 

 after drying. 



As to its use as a mordant in dyeing, I quote from 

 Mr. John Christie, of J. Orr Ewing & Co., to whom 

 I am indebted for the fine specimens of Turkey red dye- 

 ing exhibited, some of which' are finished and mordanted 

 with this new substance instead of cow dung: — "There 

 is another application of the alginate of soda that occurr- 

 ed to me might be of some interest, namely, in the 

 fixing of mordants, such as alumina or iron upon cotton 

 fibre. I find, so far as I have gone with the experiments 

 very encouraging results. I believe a very large applic' 

 atioa will be found for the alginate of soda as a dung" 

 ing substitute. The mordants, wheu precipitated, seem to" 

 have full dyeing power, the results indicating that this 

 substance is capable of taking the place of cowdung, as 

 used in print and dye-works ; also as a dunging substi- 

 tute it will rank with arseniates, phosphate, and silicate 

 of soda, and a number of other salts, which are now 

 largely used for the precipitation of mordants previous 

 to the dyeing of cotton fabrices and yarns." 



AS AN ARTICLE OF FOOD. 



Algin contaius — carbon, 44'39; hydrogen, 5'47 ; nitrogen, 

 o'77: oxygen, 4637 ; or about the same amount of nitrogen 

 found iu Dutch cheese. It has a slight pleasant marine 

 taste, easily overcome if objected to, and may form a useful 

 addition to the kitchen for thickening soups and jiuddiugs. 

 It appears specially adapted to replace gum arable in the 

 manufacture of jujubes and lozenges. To make it into jelly, 

 requires addition of gelose or gelatine or admixture of lemon 

 juice. 



It will be useful for some pharmaceutical purposes, as 

 for emulsion of oils, as an excipieut for pills and for fining 

 of spirits. 



FOR BOILER INCRUSTATION. 



The sodium alginate has a remarkable effect in resolv- 

 ing and pi eventing Hie incrustation of boilers. My friend, 

 Mr. Spiller, who introduced (he first. „nd one of tin best 

 fluids for this purpose, first suggested this application. 

 He fouud it to precipitate the lime in a state in which 

 it could be easily blown off. Further experience has fully 

 corroborated his opinion. The solution is pumped in with 

 tic feed water in the proportion of 1 lb. to every 1,000 

 gallons. Where hard waters area necessity, the saving of 

 fuel is considerable. 



FOR COVERING BOILERS. 



The seaweed charcoal, in conjunction with algin is used 

 for this purpose, and has been largely applied under the 

 name of " carbon cement." it is nearly all charcoal. 8 per 

 cent of the algin being sufficient to make it cohere. Char- 

 coal is known to lie the best solid non-conductor of heat, 

 and iu this way its application to steam boilers has been 

 made practicable. It forms a cool, light, and efficient 

 J covering, 



