\Oi.. will. No. I.] 



POPTTLAE SOTET^CK NEWS. 



Some one states that the nearer the specific gravity 

 of the liquid agrees with that of the powder the more 

 active will be the motion. \\'hile I am not pre- 

 pared to disprove this statement. I have been totally 

 luiable to verify it by experimenting with pure wa- 

 ter, pure (95 percent.) glycerin, mixtures of glycerin 

 and water, chloroform, alcohol and ether as vehicles. 

 Water gives the best results of any liquid that I have 

 tried. 



This motion should be observed by every mlcro- 

 scopist who possesses sufficiently high magnifving 

 powers to see it. Xow that we find everything 

 swarming with bacteria, there is a liability of pede- 

 sis being mistaken for some new micro-organism. 



The polariscope is a valuable accessory when ob- 

 serving the movement in crystals, but is of no avail 

 with other powders. The parabolical illuminator 

 does not seem to be serviceable in this work. The 

 best results come from oblique retieeted light passed 

 through a small diaphragm. 



Permanent mounts to illustrate the phenomenon 

 ofpedesis are not difficult to make, provided, how- 

 ever, that the motion does not cease after a few days, 

 as claimed by some authorities. I have no reason 

 for doubting the statement of one writer who says 

 he has a mount six years old that shows the move- 

 ment nicelv and as well as it e\'er did. To prepare 

 mounts. I place a well-cleaned slide on the turntable, 

 and run a ring of cement into about 0.5 m. m. (one- 

 tiftieth inch) high. This warm weather, or during 

 winter in a warm room, the cement will become 

 sufficiently dry in a half hour to permit of finishing 

 the mount. I accomplish this by placing a large 

 drop of the liquid, prepared as directed above, in a 

 cell, and placing in position a well-cleaned cover 

 glass. When the cover is pressed down, the super- 

 fiuous liquid will be pressed out. and the fresh ce- 

 ment will hold the cover glass firmly to the cell. 

 The pressure reduces the depth of the ceil to about 

 0.35 ni. m. (i-iooth inch). The slide should be 

 washed to remove any particles of the powder that 

 may have floated out with the liquid and been de- 

 posited on the cover glass. When the slide is dry 

 it is ready for use. and such a mount at least as far 

 as the mechanical part is concerned, will last a life- 

 time. Either white zinc cement or Brnnsw ick black 

 can be used. — PhniMareulinil Era. 



SCIENTIFIC BRKVITIES. 



RoM.vN Remains in Ex<ii.Axn. — A recent discox- 

 ery in Bath. England, is the recently unearthed Ro- 

 man baths. They are in ahnost complete preserva- 

 tion: the lead lining and lead piping nearly perfect, 

 the steps, the columns, the carvings, in wonderful 

 preservation, and the whole probably forminga more 

 complete specimen of this class of Roman work than 

 ixists anywhere else. 



A New I'se For the Electric Light. — The 

 liodv of a boy drowned at Winchendon. Mass.. re- 

 centlv. was found through the use of the electric 

 light, a bulb being fastened to a pole and sub- 

 merged, illuminating the water for a considerable 

 distance in the neighborhood. The electric light 

 promises to become an important aid in all manner 

 of submarine operations. 



Electric Lighting of Stages in Lonixjn. — 



Electricitv is being applied with some success to 

 the lighting of omnibuses in London. The accu- 

 nuilators are placed in a small box beneath the body 

 of the vehicle. The lamp stands in a frame, and is 

 so arranged that, by being moved a little towards 

 light or left it is lighted or extinguished. The frame 

 is connected with the accumulator by a small hidden 

 wire. One charge of the battery is sufficient for two 

 davs. The invention is in practical use on some of 

 the London omnibus lines, and is said to work ex- 

 cellently. 



Practical Cljcnjistry aijd tlje ?Irts. 



SUGAR REFININCJ. 



.Su<4ar is a peculiar product of nianv differ- 

 ent species of plants, but the <i;ieater part of 

 that consumed is obtained from the sugar 

 cane and beet root. It has lieen known in 

 the Ea.st Indies and China from a \erv re- 

 mote period, but lias onlv been generallv 

 used in Europe and America since the begin- 

 ning of the eighteenth century. Previous to 

 that time it was an expensive luxin-v instead of 

 the cheap necessitv of life which it has now 

 become. 



Beet sugar is extensively used in Europe, 

 the cultivation of the root being stimulated by 

 the governments, but in this coiintrv the sup- 

 ply is principally obtained from the sugar- 

 cane plantations of the Southern States and 

 the West Indies. The sugar-cane belongs to 

 the family of grasses, and contains about 

 eighteen per cent, of pure sugar, although 

 not more than one-half of this can be actually 

 realized. The caiies are crushed between 

 rollers, ami the expressed juice boiled down 

 to the i^roper point and allowed to cool and 

 crystallize. The moist, impure, dark-colored 

 mass of crystals obtained by this process, is 

 known as raw sugar and is shipped to the re- 

 fineries, while the liquid which drains off is 

 known as molasses, and consists of a mixture 

 of cane-sugar, inverted sugar, caramel, etc.. 

 with a liberal admixture of •■extraneous mat- 

 ter." that is — dirt. 



rile process of rehniiig the ia\\ sugar and 

 comeiling it into the white, brilliant, and 

 chemically pine ciysUils of granulated or loaf 

 sugar, is an interesting one. Tiie raw sugar 

 is dissolved in water, strained to remoye 

 the coarser im])urities and pumped into large 

 tanks, where a ciiiantity of albmnen. usually 

 in the form of ox blood, is added, and the 

 mixture heated until the albumen coagulates 

 or becomes solid. In so doing it .separates 

 out the impurities which, entangled in the 

 mass of albumen, rise to the top of the liquid 

 as a thick scum which is pressed dry and .sold 

 as a fertilizer. This process is exactly analo- 

 gous to the "clearing" of coffee with the 

 white of an egg. the only difference being in 

 the source from which the albumen is de- 

 rived. 



The solution of sugar is now perfectly clear 

 and pure, but is still of a dark color, \yliich 

 must be removetl. This is done by filtering 

 it through long iron vessels filled with bone- 

 black or charred bones coarsely ground. Tliis 

 bleaching property of bone-black is not very 

 well understood, but is a most valuable quali- 

 ty in iiiaiiy other arts besides that of sugar re- 

 fining. The impurities are doubtless attract- 

 ed and held by the pores of the bone-black, 

 as it loses the property after a while and 



must be burned over again to restore its pow- 1 tals rendering any foreign admixture evident 

 s''- , up<jn simple inspection. 



We now have a clear, colorless solution, 

 consisting principally of saccharose or crys- 

 tallizable sugar, with varying amounts of in- 

 verted or uncrystallizable sugar. It is only 

 necessary to concentrate it by boiling and al- 

 low the sugar to crystallize out. If however, 

 this is done in an open pan under the ordina- 

 ry pressure of the air, boiling will only take 

 place at a temperature sufHcienth' high to 

 "burn" the sugar and form caramel and other 

 undesirable substances. The evaporation 

 therefore takes place in a yacuuni pan, an air- 

 tight hollow vessel heated by a steam coil and 

 from which the air and water-vapor are ex- 

 hausted by a powerful pump. According to 

 the well-known principle that the boiling- 

 point of a liquid is lowered as the pressure 

 upon it diminishes, the clear syrup boils at a 

 sufficiently low temperature — from 114= to 

 150* — to prevent the alteration or decom]io- 

 sition of the sugar. This process of evapora- 

 tion requires great experience, and only a 

 thoroughly skillful workman can obtain a 

 complete and uniformly crystallized product. 

 After the concentration has reached the 

 proper point, the syrnp is drawn off and al- 

 lowed to cry.stallize, forming granulated 

 sugar. 



The motiicr-liquor or .syrup is drained 

 from the crystals and boiled o\er again and 

 a fresh crop of cry.stals obtained, and this 

 process is repeated several times. These 

 products are of inferior quality and are .sold 

 under various names as ••coffee crushed," and 

 "bnmn" .sugars. Tiiere is a popular opinion 

 that the.se sugars are sweeter tiian tiie more 

 refined article, liut this is a mistake, and they 

 are really less economical to piuchase, as 

 they contain more or less moisture and glu- 

 cose for which a comparatively high price is 

 paid. 



The crystals of granulated sugar are dried 

 without heat by a most ingenious machine 

 known as the centrifugal drier. It is a cylin- 

 drical vessel with finely perforated sides, 

 which is filled with the moist sugar and rota- 

 ted with great velocity. The water is thrown 

 ofi" through the sides by the centrifugal force, 

 leaving the sugar almost dry, a simple expos- 

 ure to warm air only being needed to com- 

 plete the process, and it is then ready to be 

 sifted into barrels and .sold in the market. 



Loaf sugar is refined in the same way, but 

 the concentrated syrup is allowed to crystal- 

 lize in conical molds, .so that it hardens into 

 a solid mass which is afterwards cut up into 

 lumps. Rock-candy is sugar which has been 

 allov\ed to crystallize slowh" so as to form 

 large crystals. 



Granulated sugar is one of the pmest arti- 

 cles of fofxl produced. It is rarely or never 

 adulterated, the characteristic form of itscrys- 



