22 



POPULAR SCIETnTCE ITEWS. 



[Fkbruary, 1888. 



AVhen starch is boiled with dihite acids, it is not 

 converted directly into starcli-sugar, but a gummy 

 substance called dextrine, and a saccharose sugar 

 known as mallosc, are first formed. These com- 

 pounds, on further boiling, are transformed into 

 starch-sugar. If the "conversion" of the starch 

 is stopped before all the maltose and dextrine have 

 disappeared, we have a sweet, gummy sirup, con- 

 taining all three, — dextrine, maltose, and starch- 

 sugar. This sirup is. the "glucose "of commerce, 

 and is manufactured as follows: The starch, ob- 

 tained usually from Indian corn by the ordinary 

 methods, is mixed with a small percentage of acid, 

 and boiled by steam-heat, either in open tubs or 

 under pressure, till a sirup is formed containing the 

 right proportion of starch-sugar. To stop the boil- 

 ing at the right point is a matter of the greatest 

 delicacy: tiie object being, to have the sirup sweet, 

 and yet not liable to solidify from excess of starch- 

 sugar. The acid sirup is then neutralized with 

 some suitable I)ase, filtered to remove impurities, 

 mechanically suspended, decolorized by passing 

 over bone-black, and concentrated to a thick, 

 viscid liquid. 



Simple as these processes seem, the successful 

 manufacturing of glucose is a matter requiring the 

 greatest nicety of detail. Tlie product is practically 

 colorless, perfectly transparent, neutral, and con- 

 tains only about two-tenths of one per cent of 

 foreign salts. The finest grades of glucose are 

 u.sed by confectioners; ordinary candies containing 

 thirty to ninety per cent, and the cheaper kind of 

 gum-drops being practically pure glucose. 



Glucose, being a colorless neutral sweet in a state 

 of almost absolute purity, is excellently adapted 

 for use in tiie manufacture of soda-water, sirups, 

 jellies, and similar products. It is extensively mixed 

 with cane-sugar sirups, but can hardly be consid- 

 ered an adulterant in the ordinary acceptance of 

 the term, as its cost per gallon is much more than 

 that of cane-sugar sirup. 



In spite of the fact that the components of com- 

 mercial glucose — dextrine, maltose, and starch- 

 sugar — enter into so many natural food-products, 

 starch-sugar also playing such an important part 

 in the digestive functions, this product has been 

 condemn! d by many as unwholesome and even 

 poisonous. 



This idea has arisen from the fact that in the man- 

 ufacture of glucose strong mineral acids are used. 



It is generally known that such acids in a 

 concentrated state, when taken into the system, 

 quickly produce death. The popular mind, pos- 

 sessed of the one fact that mineral acids are used 

 in this process, but ignorant of the details, imme- 

 diately jumped at the conclusion that glucose was 

 necessarily poisonous, and should be condemned 

 as an article of food. 



Now, the facts of the case are these: — 



I. The acid used does not combine ciiemically 

 with either starch or glucose, but in some unex- 

 l)lained way, by its presence acting in concert with 

 the water and heat, produces the change in the 

 starch, so tiiat at the end of the process there is 

 just as much free acid as in the beginning. 



II. 'l"he amount of acid is exceedingly small, — 

 a few ]ioundjs dissolved in maTiy liundreds of gal- 

 lons of water sufficing the purpose 



III. 'IMiis acid is exactly neutralized with some 

 basic substance, — soda, lime, or potash, — forming 

 such harmless salts as calcic sulphate (gypsum), 

 sodic sulphate (Glauber's-salts), or sodic chloride 

 (connnon salt). 



IV. These salts are never present in more than 

 two or three tenths of one per cent, — often in no 

 greater quantity than in some hard waters, — and 

 iheir presence can only be proved by delicate chem- 

 ical tests. 



Few food-products, therefore, can boast of the 

 remarkable purity of commercial glucose. 



Tliere are eight glucose establishments in the 

 United States, having a capacity to consume about 

 twelve millions of bushels of corn annually, and 

 making over three hundred and sixty million 

 pounds of glucose. 



This immense industry has sprung into exist- 

 ence within the last dozen years. 



A HAKMLESS RED COLOR FOR CONFEC- 

 TIONERS AND OTHERS. 



Gawat.ovski recommends, as a harmless red 

 color for confectionery and all sorts of eatables, the 

 extract of the led flower of the poppy (Papaier 

 7-Jiosns). This plant, which grows everywhere 

 throughout Europe, produces in June or July the 

 well-known flower in abundance, the leaves of which, 

 when dried, yield, besides about twelve per cent 

 fat, twenty per cent gum and twentj'-eight per 

 cent vegetable fibre ; also about forty per cent 

 of red dye, which is the basis of si/ruptis rhceado.i 

 (German pharmacopeia). This substance may be 

 used as it is, or the pure color may be extracted 

 from the fresh-gathered leaves, by putting them hi 

 a clean bottle, pouring sulphuric ether on them, and 

 allowing the bottle to remain well corked and im- 

 disturbed for about two hours in a cool place. The 

 ether, which may serve twice or three times for 

 the same operation with fresh leaves, is then poured 

 oif , and undiluted alcohol poured over the leaves. 

 After three or four hours the entire coloring mat- 

 ter of the poppy-flower has been extracted, and is 

 contained in the alcohol, and may be used either as 

 it is, in the alcoholic solution, or after having been 

 evaporated and re-dissolved in water containing 

 sugar (.sirup). 



This red dye has the following qualities in rela- 

 tion to solutions and tests, according to the experi- 

 ments of Gawalovski: — 



1. It is unsoluble in ether (ethylether), benzaate 

 of chloroform, and amyl alcohol. 



2. It is soluble in water, spirits of wine, and 

 methylated spirits, turning to a light-red color. 



3 Metallic acids and organic acids turn the solu- 

 tions named in 1 and 2 a bright red, except 

 nitric acid, which, when cold and diluted, turns the 

 color gradually, but when hot, and in any degree 

 of concentration, changes the color into yellow, and 

 destroys it altogether. 



4. A solution of alum dyes it bright red; a solu- 

 tion of soda precipitates a violet powder. 



5. Caustic soda and potash turn the color a 

 brown red, which can be neutralized by diluted 

 mineral acids and organic acids. 



(Jawalovski concludes his report to the German 

 " spirit industry " with the remark that this is a 

 very innocuous color, easy distinguishable from tar 

 colois, and highly useful and satisfactory to those 

 who have to color articles of food. — Practical 

 Confectioner. 



MAGIC PHOTOGRAPHS. 



The following is taken from the Druggists' Cir- 

 cular : " This name is given to a new sort of pho- 

 tographic prints now sold in Paris. When sold the 

 paper is perfectly white, and the image appears on 

 dipping the pasteboard in water. The photographs 

 in question are obtained as follows: — 



" With any desired negative a proof is printed 

 on ordinary chloride-of-silver paper, such as can 

 be procured from all dealeis in photographic ma- 

 terials The positive is next fixed with a bath 

 containing ten per cent of hyposulphite of sodium. 

 The ])iint must not be toned with gold, but most 

 carefully washed with water, so as to leave in the 

 pajier HO trfice gf hyposulphite. This is absolutely 



necessary for the production of an invisible image. 

 " The print is now placed in a bath composed 

 as follows : — 

 Take of 



Bichloride of mercury 5 gra. 



Water 100 " 



" The image there gradually fades away, and 

 finally disappears altogether. The paper, having 

 been thoroughly washed a second time, is dried, 

 and the photograph is ready to be mounted. In 

 mounting the photograph, a small piece of blotting- 

 paper impregnated with hyposulphite or sulphite 

 of sodium is posted between the albumen paper/ 

 and the pasteboard, or behind the pasteboard, so 

 that, on being dipped in water, the sulphite dissolves, 

 and develops the image. 



" The following is the explanation of the chemi- 

 cal changes which take place: The first imago, 

 obtained from the usual printing with a negative, 

 owes its color to reduced silver. On contact with 

 the corrosive-sublimate solution, chloride of silver 

 and calomel are formed, both of which are color- 

 less, but turn black in presence of sulphites or 

 hyposulphites. The final image owes, therefore, 

 its color to sulphide of mercury, with pi-obably 

 sulphide of silver." 



The bichloride of mercury must be used with 



care, as it is highly poisonous when swallowed. 



— • — 



INDUSTRIAL MEMORANDA. 



The " Times " of Lsoia contains a description 

 of a remarkable engineering undertaking atGokak, 

 where three turbines, each two hundred and fifty 

 hoise power, transmit power by rope gearing to a 

 cotton-mill at a distance of seven hundred and 

 thirty-nine feet, the first three hundred feet being 

 up the face of a perpendicular cliff. The work ap- 

 pears to have been carried out in an especially 

 skilful manner. 



A Cabling Feat. — A remarkable feat of 

 cabling matter has been accomplished by the New 

 York Times, which published, on Nov. 18, the 

 whole of Mr. Swinburne's new tragedy, Loc- 

 ri»e, forwarded by its London correspondent. 

 The tragedy filled two nonpareil pages — fourteen 

 columns — of the paper, and formed a '-cable- 

 gram" of 18,000 words. We learn that part of 

 this — 10,000 words — came over the Commercial 

 Cable Company's lines, and the remaining part 

 was transmitted by the \Vestern Union The por- 

 tions handled by the Commercial cable covered 

 1 ,050 feet of paper tape. The cablegram was taken 

 at the rate of nearly 17 words per minute, and kept 

 the two cables of the company busy for five hours. 

 It is believed that this is the first time that such an 

 important literary work has been sent over by cable. 

 It is interesting to note that the tragedy of Loc- 

 rine, if printed in ordinary book form, would fill 

 72 pages of 2.50 words to the page. 



Celi.ui.oid. — Among the various uses of cellu- 

 loid, it would appear to be a suitable sheathing for 

 ships, in place of copper. A French company now 

 undertakes to supply the substance for this at nine 

 francs per surface meter, and per millimeter of 

 thickness. In experiments by M. Butaine, plates 

 of celluloid applied to various vessels in January 

 last were removed five or six months after, and 

 found quite intact and free from marine vegetation, 

 which was abundant on parts uncovered. The 

 color of the substance is indestructible; the thick- 

 ness may be reduced to 0.0003 metre; and the 

 qualities of elasticity, solidity, impermeability, re- 

 sistance to chemical action, etc , are all in favor 

 of this use of celluloid. 



A SiiiEuiAN Pacific Railroad. — The great 

 scheme for a thiongh Siberian Railway fiom St. 

 I'etersburg to Vladivostock, the naval port on the 

 Pacific, is making progress, Coniniunicatiou is 



