Vol. XXII. No. 2.] 



POPULAR SCIENCE NEWS. 



21 



Practical Ci)emtstrp anH tist ^xUf. 



SIMPLE 



AND CHEAP 

 APPARATUS. 



CHEMICAL 



Fio. 1. 



In the June number of this journal a water- 

 pump for producing a vacuum for filtering- 

 purposes was described and illustrated. It 

 was to be made of brass or other metal, and 

 could onlj- be constructed b3' a practical brass- 

 worker. Mr. Robert Law, in the Chemical 

 ^News, describes a simple form of this appara- 

 tus, which can be made 

 by any chemist from 

 pieces of ordinary glass 

 tubing. It is con- 

 structed as follows : 

 Select a piece of stout ^ 

 glass tubing 3 inches 

 long and | inch bore ; 

 fit this with corks, — 

 one with two holes, the " 

 other with one hole. 

 Now take three pieces 

 of ordinary glass tubing 

 •j>, inch bore, and draw 

 two of them out, as 

 shown in Fig. 1. Cut 

 the one at a and tiie 

 other at b; bend the 

 third piece at an angle 

 of 90°. Insert xa and the bent piece through 

 one cork, and xb through the other, so that xa 

 will project inside of xb. Attach xa to a 

 water- supph'. On allowing water to run 

 through the apparatus, a vacuum will be 

 caused in the tube N; and, if connected as 

 shown in sketch, the process of (illration 

 will be greatly facilitated. This apparatus has 

 given a vacuum as high as 28.5 inches of 

 mercury. 



Mr. II. N. Warren, in the same journal, 

 describes a simple apparatus for preparing large 

 quantities of sulphurous-acid gas. It consists 

 of a glass vessel, A, provided with three lubu- 

 lars, otherwise resembling a large Wolff bottle ; 

 the large tube Ti being 

 provided with a slop- 

 I per for the purpose of 

 introducing pieces of 

 sulphur from time to 

 time into the small 

 dish, C, intended for 

 its reception, and fed 

 with air by means of 

 the delivery tube, D, 

 thus allowing the 

 stream of gas caused 

 by the consumption of the sulphur to escape 

 by means of the exit tube, E, to the vessel 

 desired to receive it. 



In using the apparatus, the sulphur is first 

 kindled by introducing a red-hot wire through 

 the tube B. an<l replacing the stopper tliat has 

 been momentarily removed for the introduction 

 of the same. A slight blast is now maintained 

 from the bellows that are in connection with 

 the pipe Z>, until the whole of the sulphur is 

 thoroughly kindled, when a somewiiat more 

 powerful blast may be applied. By subsli- 



Fio. 2. 



tu'ting phosphorus or carbon for the sulphur, 

 phosphoric anhydride or carbonic dio.xide can 

 also be made in any desired quantity. 



The Journal of Analytical Chemistry also 

 describes a form of the well-known Liebig 



Fio. 3. 



condenser, which has the advantage of sim- 

 plicity and considerable flexibilitj-. As will 

 be seen from the illustration, it consists of two 

 plain glass tubes, connected together by a 

 piece of stout rubber tubing, b. Through a 

 hole in this a small piece of glass tubing, witli 

 a shoulder fused at the inner end, is pushed, 

 which serves for the passage of water. 



A NEW FORM OF VENTILATOR. 

 This novel form of ventilator is the inven- 

 tion of M. Becker, and is described in La 

 Nature. It is constructed on the same prin- 

 ciple as the steam-injector, so universall}" used 

 for feeding water into steam-boilers. It con- 



sists of a revolving cap provided with a vane 

 which turns it away from the wind. Inside 

 the cap is a tube with an exterior opening, 

 through which the wind blows in the direction 

 of the arrows. This current induces another 

 current in an upward direction through the 

 chimney, just as the jet of steam passing 

 through an injector carries along with it a 

 stream of water. A more familiar illustration 

 of the same principle is seen in the common 

 perfume atomizer, in which a current of air, 

 passing across the top of a tube dipping into 

 the perfume, draws the liquid up through the 

 tube, and blows it into a fine spraj'. 



As this form of ventilator is not dependent 

 upon a current of heated air from the fire, it 

 is also applicable to the ventilation of closed 

 chambers, vaults, and similar places where 

 offensive or dangerous gases are present. 

 The principal disadvantage is, that it does not 



operate in calm weather ; but there are onl3- a 

 very few days when there is not sufficient 

 wind to cause more or less air to pass through it. 



[Original in Popular Science yews.] 



STARCH-SUGAR AND GLUCOSE. 



BY GEORGE W. KOI.FE, A.M. 



As long ago as 1811, Kirclioff, a Russian chemist, 

 noticed that starch, when boiled with dilute acids, 

 was transformed into a sweet substance re.serabling 

 ordinary sugar. Indeed, Kirchoff supposed it to 

 be identical with the sugar of the sugar-cane. 



The French took great interest in this discovery 

 of Kirchoff; for France at that time had entered 

 into the long and bloody wars of the first Napoleon, 

 and was cut off fiom her sugar-supplies by the 

 blockade. Starch, however, being plenty in their 

 country, the French at once with the greatest en- 

 thusiasm began the manufacture of this new sugar, 

 which seemed to present no difficulties. Rut they 

 soon found that their product was radically differ- 

 ent from cane-sugar. By no method could the 

 soft, waxy substance be converted into the hard, 

 shining crystals so characteristic of the sugar 

 brought from America and India; besides, the 

 starch- sugar had much less sweetening power, and 

 consequently made but a poor substitute. 



The French spent much time and ingenuity in 

 vain attempts to make cane-sugar out of the new 

 sweet, but finally gave it up, for after the war, cane- 

 sugar again became plentiful, and so there was no 

 stimulus for further effort in this direction. 



Although for over fifty years starch-sugar ha.s 

 been put to but little practical use, except in a 

 small way in the manufacture of beer, and as an 

 adulterant of the poorer grades of cane-sugar, yet 

 to the scientific world it has proved of the greatest 

 interest. It has been found to occur widely in the 

 vegetable kingdom, being the natural sweet of 

 most fruits: hence its popular name, " gr.ipe- 

 sugar." 



Investigations into the chemical nature of this 

 substance led to the discovery of many other sugars, 

 till at present at least fifteen distinct sugars aie 

 known. All of these can be ranked into- two dis- 

 tinct classes, — the glucoses of general chemical 

 formula CjlIijO,,; and the saccharoses, C,.IIjjOu. 



Starch-sugar is a (jlucose, while cane-sugar be- 

 longs to the latter class. 



Boiling with dilute acids converts a saccharose 

 into a glucose; but unfortunately, as our Frencli 

 friends found, no art of the chemist has as yet 

 been able to convert a glucose back to a saccharose. 

 All housekeepers who have had occasion to put up 

 fruit preserves have doubtless noticed the mysterious 

 loss of sweetening power in cane-sugar caused by 

 this incersion, as it is called; the cane-sugar being 

 transformed into two glucoses of inferior sweet- 

 ening power, — starcli-sugar, or dextrose as it some- 

 times called, and lieouto.ie. 



C'.jIIhO.i + H,0 

 Cane-sugar -^ watei-. 



C',,II,20„ + CeH.jOo. 

 Dextrose -t- laevuluse. 



The acid does not enter into combination with 

 the sugar in this reaction. 



Starch-sugar plays an important part in the 

 digestive and circulatory functions. Every particle 

 of starch eaten must be converted into this glucose 

 by the digestive fluids before it can be utilized by 

 the blood. This sugar is also produced in the liver 

 in considerable quantities. 



While the pure starch-sugar has but a limited 

 practical application, a sirup containing starch- 

 sugar has of late years become of great commer- 

 cial value. This article, known in trade as <//ucose, 

 depends on the following chemical principles for 

 its manufacture: — 



